• SqlHelper(带详细中文注释)


    using System;
    using System.Data;
    using System.Xml;
    using System.Data.SqlClient;
    using System.Collections;

    namespace hkszyy
    {
     /// <summary>
     /// SqlServer数据访问帮助类
     /// </summary>
     public sealed class SqlHelper
     {
      #region 私有构造函数和方法

      private SqlHelper() {}

      /// <summary>
      /// 将SqlParameter参数数组(参数值)分配给SqlCommand命令.
      /// 这个方法将给任何一个参数分配DBNull.Value;
      /// 该操作将阻止默认值的使用.
      /// </summary>
      /// <param name="command">命令名</param>
      /// <param name="commandParameters">SqlParameters数组</param>
      private static void AttachParameters(SqlCommand command, SqlParameter[] commandParameters)
      {
       if( command == null ) throw new ArgumentNullException( "command" );
       if( commandParameters != null )
       {
        foreach (SqlParameter p in commandParameters)
        {
         if( p != null )
         {
          // 检查未分配值的输出参数,将其分配以DBNull.Value.
          if ( ( p.Direction == ParameterDirection.InputOutput || p.Direction == ParameterDirection.Input ) &&
           (p.Value == null))
          {
           p.Value = DBNull.Value;
          }
          command.Parameters.Add(p);
         }
        }
       }
      }

      /// <summary>
      /// 将DataRow类型的列值分配到SqlParameter参数数组.
      /// </summary>
      /// <param name="commandParameters">要分配值的SqlParameter参数数组</param>
      /// <param name="dataRow">将要分配给存储过程参数的DataRow</param>
      private static void AssignParameterValues(SqlParameter[] commandParameters, DataRow dataRow)
      {
       if ((commandParameters == null) || (dataRow == null))
       {
        return;
       }

       int i = 0;
       // 设置参数值
       foreach(SqlParameter commandParameter in commandParameters)
       {
        // 创建参数名称,如果不存在,只抛出一个异常.
        if( commandParameter.ParameterName == null ||
         commandParameter.ParameterName.Length <= 1 )
         throw new Exception(
          string.Format("请提供参数{0}一个有效的名称{1}.", i, commandParameter.ParameterName ) );
        // 从dataRow的表中获取为参数数组中数组名称的列的索引.
        // 如果存在和参数名称相同的列,则将列值赋给当前名称的参数.
        if (dataRow.Table.Columns.IndexOf(commandParameter.ParameterName.Substring(1)) != -1)
         commandParameter.Value = dataRow[commandParameter.ParameterName.Substring(1)];
        i++;
       }
      }

      /// <summary>
      /// 将一个对象数组分配给SqlParameter参数数组.
      /// </summary>
      /// <param name="commandParameters">要分配值的SqlParameter参数数组</param>
      /// <param name="parameterValues">将要分配给存储过程参数的对象数组</param>
      private static void AssignParameterValues(SqlParameter[] commandParameters, object[] parameterValues)
      {
       if ((commandParameters == null) || (parameterValues == null))
       {
        return;
       }

       // 确保对象数组个数与参数个数匹配,如果不匹配,抛出一个异常.
       if (commandParameters.Length != parameterValues.Length)
       {
        throw new ArgumentException("参数值个数与参数不匹配.");
       }

       // 给参数赋值
       for (int i = 0, j = commandParameters.Length; i < j; i++)
       {
        // If the current array value derives from IDbDataParameter, then assign its Value property
        if (parameterValues[i] is IDbDataParameter)
        {
         IDbDataParameter paramInstance = (IDbDataParameter)parameterValues[i];
         if( paramInstance.Value == null )
         {
          commandParameters[i].Value = DBNull.Value;
         }
         else
         {
          commandParameters[i].Value = paramInstance.Value;
         }
        }
        else if (parameterValues[i] == null)
        {
         commandParameters[i].Value = DBNull.Value;
        }
        else
        {
         commandParameters[i].Value = parameterValues[i];
        }
       }
      }

      /// <summary>
      /// 预处理用户提供的命令,数据库连接/事务/命令类型/参数
      /// </summary>
      /// <param name="command">要处理的SqlCommand</param>
      /// <param name="connection">数据库连接</param>
      /// <param name="transaction">一个有效的事务或者是null值</param>
      /// <param name="commandType">命令类型 (存储过程,命令文本, 其它.)</param>
      /// <param name="commandText">存储过程名或都T-SQL命令文本</param>
      /// <param name="commandParameters">和命令相关联的SqlParameter参数数组,如果没有参数为'null'</param>
      /// <param name="mustCloseConnection"><c>true</c> 如果连接是打开的,则为true,其它情况下为false.</param>
      private static void PrepareCommand(SqlCommand command, SqlConnection connection, SqlTransaction transaction, CommandType commandType, string commandText, SqlParameter[] commandParameters, out bool mustCloseConnection )
      {
       if( command == null ) throw new ArgumentNullException( "command" );
       if( commandText == null || commandText.Length == 0 ) throw new ArgumentNullException( "commandText" );

       // If the provided connection is not open, we will open it
       if (connection.State != ConnectionState.Open)
       {
        mustCloseConnection = true;
        connection.Open();
       }
       else
       {
        mustCloseConnection = false;
       }

       // 给命令分配一个数据库连接.
       command.Connection = connection;

       // 设置命令文本(存储过程名或SQL语句)
       command.CommandText = commandText;

       // 分配事务
       if (transaction != null)
       {
        if( transaction.Connection == null ) throw new ArgumentException( "The transaction was rollbacked or commited, please provide an open transaction.", "transaction" );
        command.Transaction = transaction;
       }

       // 设置命令类型.
       command.CommandType = commandType;

       // 分配命令参数
       if (commandParameters != null)
       {
        AttachParameters(command, commandParameters);
       }
       return;
      }

      #endregion 私有构造函数和方法结束

      #region ExecuteNonQuery命令

      /// <summary>
      /// 执行指定连接字符串,类型的SqlCommand.
      /// </summary>
      /// <remarks>
      /// 示例: 
      ///  int result = ExecuteNonQuery(connString, CommandType.StoredProcedure, "PublishOrders");
      /// </remarks>
      /// <param name="connectionString">一个有效的数据库连接字符串</param>
      /// <param name="commandType">命令类型 (存储过程,命令文本, 其它.)</param>
      /// <param name="commandText">存储过程名称或SQL语句</param>
      /// <returns>返回命令影响的行数</returns>
      public static int ExecuteNonQuery(string connectionString, CommandType commandType, string commandText)
      {
       return ExecuteNonQuery(connectionString, commandType, commandText, (SqlParameter[])null);
      }

      /// <summary>
      /// 执行指定连接字符串,类型的SqlCommand.如果没有提供参数,不返回结果.
      /// </summary>
      /// <remarks>
      /// 示例: 
      ///  int result = ExecuteNonQuery(connString, CommandType.StoredProcedure, "PublishOrders", new SqlParameter("@prodid", 24));
      /// </remarks>
      /// <param name="connectionString">一个有效的数据库连接字符串</param>
      /// <param name="commandType">命令类型 (存储过程,命令文本, 其它.)</param>
      /// <param name="commandText">存储过程名称或SQL语句</param>
      /// <param name="commandParameters">SqlParameter参数数组</param>
      /// <returns>返回命令影响的行数</returns>
      public static int ExecuteNonQuery(string connectionString, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
      {
       if( connectionString == null || connectionString.Length == 0 ) throw new ArgumentNullException( "connectionString" );

       using (SqlConnection connection = new SqlConnection(connectionString))
       {
        connection.Open();

        return ExecuteNonQuery(connection, commandType, commandText, commandParameters);
       }
      }

      /// <summary>
      /// 执行指定连接字符串的存储过程,将对象数组的值赋给存储过程参数,
      /// 此方法需要在参数缓存方法中探索参数并生成参数.
      /// </summary>
      /// <remarks>
      /// 这个方法没有提供访问输出参数和返回值.
      /// 示例: 
      ///  int result = ExecuteNonQuery(connString, "PublishOrders", 24, 36);
      /// </remarks>
      /// <param name="connectionString">一个有效的数据库连接字符串/param>
      /// <param name="spName">存储过程名称</param>
      /// <param name="parameterValues">分配到存储过程输入参数的对象数组</param>
      /// <returns>返回受影响的行数</returns>
      public static int ExecuteNonQuery(string connectionString, string spName, params object[] parameterValues)
      {
       if( connectionString == null || connectionString.Length == 0 ) throw new ArgumentNullException( "connectionString" );
       if( spName == null || spName.Length == 0 ) throw new ArgumentNullException( "spName" );

       // 如果存在参数值
       if ((parameterValues != null) && (parameterValues.Length > 0))
       {
        // 从探索存储过程参数(加载到缓存)并分配给存储过程参数数组.
        SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(connectionString, spName);

        // 给存储过程参数赋值
        AssignParameterValues(commandParameters, parameterValues);

        return ExecuteNonQuery(connectionString, CommandType.StoredProcedure, spName, commandParameters);
       }
       else
       {
        // 没有参数情况下
        return ExecuteNonQuery(connectionString, CommandType.StoredProcedure, spName);
       }
      }

      /// <summary>
      /// 执行指定数据库连接对象的命令
      /// </summary>
      /// <remarks>
      /// 示例: 
      ///  int result = ExecuteNonQuery(conn, CommandType.StoredProcedure, "PublishOrders");
      /// </remarks>
      /// <param name="connection">一个有效的数据库连接对象</param>
      /// <param name="commandType">命令类型(存储过程,命令文本或其它.)</param>
      /// <param name="commandText">存储过程名称或T-SQL语句</param>
      /// <returns>返回影响的行数</returns>
      public static int ExecuteNonQuery(SqlConnection connection, CommandType commandType, string commandText)
      {
       return ExecuteNonQuery(connection, commandType, commandText, (SqlParameter[])null);
      }

      /// <summary>
      /// 执行指定数据库连接对象的命令
      /// </summary>
      /// <remarks>
      /// 示例: 
      ///  int result = ExecuteNonQuery(conn, CommandType.StoredProcedure, "PublishOrders", new SqlParameter("@prodid", 24));
      /// </remarks>
      /// <param name="connection">一个有效的数据库连接对象</param>
      /// <param name="commandType">命令类型(存储过程,命令文本或其它.)</param>
      /// <param name="commandText">T存储过程名称或T-SQL语句</param>
      /// <param name="commandParameters">SqlParamter参数数组</param>
      /// <returns>返回影响的行数</returns>
      public static int ExecuteNonQuery(SqlConnection connection, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
      {   
       if( connection == null ) throw new ArgumentNullException( "connection" );

       // 创建SqlCommand命令,并进行预处理
       SqlCommand cmd = new SqlCommand();
       bool mustCloseConnection = false;
       PrepareCommand(cmd, connection, (SqlTransaction)null, commandType, commandText, commandParameters, out mustCloseConnection );
               
       // Finally, execute the command
       int retval = cmd.ExecuteNonQuery();
               
       // 清除参数,以便再次使用.
       cmd.Parameters.Clear();
       if( mustCloseConnection )
        connection.Close();
       return retval;
      }

      /// <summary>
      /// 执行指定数据库连接对象的命令,将对象数组的值赋给存储过程参数.
      /// </summary>
      /// <remarks>
      /// 此方法不提供访问存储过程输出参数和返回值
      /// 示例: 
      ///  int result = ExecuteNonQuery(conn, "PublishOrders", 24, 36);
      /// </remarks>
      /// <param name="connection">一个有效的数据库连接对象</param>
      /// <param name="spName">存储过程名</param>
      /// <param name="parameterValues">分配给存储过程输入参数的对象数组</param>
      /// <returns>返回影响的行数</returns>
      public static int ExecuteNonQuery(SqlConnection connection, string spName, params object[] parameterValues)
      {
       if( connection == null ) throw new ArgumentNullException( "connection" );
       if( spName == null || spName.Length == 0 ) throw new ArgumentNullException( "spName" );

       // 如果有参数值
       if ((parameterValues != null) && (parameterValues.Length > 0))
       {
        // 从缓存中加载存储过程参数
        SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(connection, spName);

        // 给存储过程分配参数值
        AssignParameterValues(commandParameters, parameterValues);

        return ExecuteNonQuery(connection, CommandType.StoredProcedure, spName, commandParameters);
       }
       else
       {
        return ExecuteNonQuery(connection, CommandType.StoredProcedure, spName);
       }
      }

      /// <summary>
      /// 执行带事务的SqlCommand.
      /// </summary>
      /// <remarks>
      /// 示例.: 
      ///  int result = ExecuteNonQuery(trans, CommandType.StoredProcedure, "PublishOrders");
      /// </remarks>
      /// <param name="transaction">一个有效的数据库连接对象</param>
      /// <param name="commandType">命令类型(存储过程,命令文本或其它.)</param>
      /// <param name="commandText">存储过程名称或T-SQL语句</param>
      /// <returns>返回影响的行数/returns>
      public static int ExecuteNonQuery(SqlTransaction transaction, CommandType commandType, string commandText)
      {
       return ExecuteNonQuery(transaction, commandType, commandText, (SqlParameter[])null);
      }

      /// <summary>
      /// 执行带事务的SqlCommand(指定参数).
      /// </summary>
      /// <remarks>
      /// 示例: 
      ///  int result = ExecuteNonQuery(trans, CommandType.StoredProcedure, "GetOrders", new SqlParameter("@prodid", 24));
      /// </remarks>
      /// <param name="transaction">一个有效的数据库连接对象</param>
      /// <param name="commandType">命令类型(存储过程,命令文本或其它.)</param>
      /// <param name="commandText">存储过程名称或T-SQL语句</param>
      /// <param name="commandParameters">SqlParamter参数数组</param>
      /// <returns>返回影响的行数</returns>
      public static int ExecuteNonQuery(SqlTransaction transaction, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
      {
       if( transaction == null ) throw new ArgumentNullException( "transaction" );
       if( transaction != null && transaction.Connection == null ) throw new ArgumentException( "The transaction was rollbacked or commited, please provide an open transaction.", "transaction" );

       // 预处理
       SqlCommand cmd = new SqlCommand();
       bool mustCloseConnection = false;
       PrepareCommand(cmd, transaction.Connection, transaction, commandType, commandText, commandParameters, out mustCloseConnection );
                   
       // 执行
       int retval = cmd.ExecuteNonQuery();
                   
       // 清除参数集,以便再次使用.
       cmd.Parameters.Clear();
       return retval;
      }

      /// <summary>
      /// 执行带事务的SqlCommand(指定参数值).
      /// </summary>
      /// <remarks>
      /// 此方法不提供访问存储过程输出参数和返回值
      /// 示例: 
      ///  int result = ExecuteNonQuery(conn, trans, "PublishOrders", 24, 36);
      /// </remarks>
      /// <param name="transaction">一个有效的数据库连接对象</param>
      /// <param name="spName">存储过程名</param>
      /// <param name="parameterValues">分配给存储过程输入参数的对象数组</param>
      /// <returns>返回受影响的行数</returns>
      public static int ExecuteNonQuery(SqlTransaction transaction, string spName, params object[] parameterValues)
      {
       if( transaction == null ) throw new ArgumentNullException( "transaction" );
       if( transaction != null && transaction.Connection == null ) throw new ArgumentException( "The transaction was rollbacked or commited, please provide an open transaction.", "transaction" );
       if( spName == null || spName.Length == 0 ) throw new ArgumentNullException( "spName" );

       // 如果有参数值
       if ((parameterValues != null) && (parameterValues.Length > 0))
       {
        // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
        SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(transaction.Connection, spName);

        // 给存储过程参数赋值
        AssignParameterValues(commandParameters, parameterValues);

        // 调用重载方法
        return ExecuteNonQuery(transaction, CommandType.StoredProcedure, spName, commandParameters);
       }
       else
       {
        // 没有参数值
        return ExecuteNonQuery(transaction, CommandType.StoredProcedure, spName);
       }
      }

      #endregion ExecuteNonQuery方法结束

      #region ExecuteDataset方法

      /// <summary>
      /// 执行指定数据库连接字符串的命令,返回DataSet.
      /// </summary>
      /// <remarks>
      /// 示例: 
      ///  DataSet ds = ExecuteDataset(connString, CommandType.StoredProcedure, "GetOrders");
      /// </remarks>
      /// <param name="connectionString">一个有效的数据库连接字符串</param>
      /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
      /// <param name="commandText">存储过程名称或T-SQL语句</param>
      /// <returns>返回一个包含结果集的DataSet</returns>
      public static DataSet ExecuteDataset(string connectionString, CommandType commandType, string commandText)
      {
       return ExecuteDataset(connectionString, commandType, commandText, (SqlParameter[])null);
      }

      /// <summary>
      /// 执行指定数据库连接字符串的命令,返回DataSet.
      /// </summary>
      /// <remarks>
      /// 示例:
      ///  DataSet ds = ExecuteDataset(connString, CommandType.StoredProcedure, "GetOrders", new SqlParameter("@prodid", 24));
      /// </remarks>
      /// <param name="connectionString">一个有效的数据库连接字符串</param>
      /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
      /// <param name="commandText">存储过程名称或T-SQL语句</param>
      /// <param name="commandParameters">SqlParamters参数数组</param>
      /// <returns>返回一个包含结果集的DataSet</returns>
      public static DataSet ExecuteDataset(string connectionString, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
      {
       if( connectionString == null || connectionString.Length == 0 ) throw new ArgumentNullException( "connectionString" );

       // 创建并打开数据库连接对象,操作完成释放对象.
       using (SqlConnection connection = new SqlConnection(connectionString))
       {
        connection.Open();

        // 调用指定数据库连接字符串重载方法.
        return ExecuteDataset(connection, commandType, commandText, commandParameters);
       }
      }

      /// <summary>
      /// 执行指定数据库连接字符串的命令,直接提供参数值,返回DataSet.
      /// </summary>
      /// <remarks>
      /// 此方法不提供访问存储过程输出参数和返回值.
      /// 示例:
      ///  DataSet ds = ExecuteDataset(connString, "GetOrders", 24, 36);
      /// </remarks>
      /// <param name="connectionString">一个有效的数据库连接字符串</param>
      /// <param name="spName">存储过程名</param>
      /// <param name="parameterValues">分配给存储过程输入参数的对象数组</param>
      /// <returns>返回一个包含结果集的DataSet</returns>
      public static DataSet ExecuteDataset(string connectionString, string spName, params object[] parameterValues)
      {
       if( connectionString == null || connectionString.Length == 0 ) throw new ArgumentNullException( "connectionString" );
       if( spName == null || spName.Length == 0 ) throw new ArgumentNullException( "spName" );
               
       if ((parameterValues != null) && (parameterValues.Length > 0))
       {
        // 从缓存中检索存储过程参数
        SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(connectionString, spName);

        // 给存储过程参数分配值
        AssignParameterValues(commandParameters, parameterValues);

        return ExecuteDataset(connectionString, CommandType.StoredProcedure, spName, commandParameters);
       }
       else
       {
        return ExecuteDataset(connectionString, CommandType.StoredProcedure, spName);
       }
      }

      /// <summary>
      /// 执行指定数据库连接对象的命令,返回DataSet.
      /// </summary>
      /// <remarks>
      /// 示例: 
      ///  DataSet ds = ExecuteDataset(conn, CommandType.StoredProcedure, "GetOrders");
      /// </remarks>
      /// <param name="connection">一个有效的数据库连接对象</param>
      /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
      /// <param name="commandText">存储过程名或T-SQL语句</param>
      /// <returns>返回一个包含结果集的DataSet</returns>
      public static DataSet ExecuteDataset(SqlConnection connection, CommandType commandType, string commandText)
      {
       return ExecuteDataset(connection, commandType, commandText, (SqlParameter[])null);
      }
           
      /// <summary>
      /// 执行指定数据库连接对象的命令,指定存储过程参数,返回DataSet.
      /// </summary>
      /// <remarks>
      /// 示例: 
      ///  DataSet ds = ExecuteDataset(conn, CommandType.StoredProcedure, "GetOrders", new SqlParameter("@prodid", 24));
      /// </remarks>
      /// <param name="connection">一个有效的数据库连接对象</param>
      /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
      /// <param name="commandText">存储过程名或T-SQL语句</param>
      /// <param name="commandParameters">SqlParamter参数数组</param>
      /// <returns>返回一个包含结果集的DataSet</returns>
      public static DataSet ExecuteDataset(SqlConnection connection, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
      {
       if( connection == null ) throw new ArgumentNullException( "connection" );

       // 预处理
       SqlCommand cmd = new SqlCommand();
       bool mustCloseConnection = false;
       PrepareCommand(cmd, connection, (SqlTransaction)null, commandType, commandText, commandParameters, out mustCloseConnection );
                   
       // 创建SqlDataAdapter和DataSet.
       using( SqlDataAdapter da = new SqlDataAdapter(cmd) )
       {
        DataSet ds = new DataSet();

        // 填充DataSet.
        da.Fill(ds);
                   
        cmd.Parameters.Clear();

        if( mustCloseConnection )
         connection.Close();

        return ds;
       }   
      }
           
      /// <summary>
      /// 执行指定数据库连接对象的命令,指定参数值,返回DataSet.
      /// </summary>
      /// <remarks>
      /// 此方法不提供访问存储过程输入参数和返回值.
      /// 示例.: 
      ///  DataSet ds = ExecuteDataset(conn, "GetOrders", 24, 36);
      /// </remarks>
      /// <param name="connection">一个有效的数据库连接对象</param>
      /// <param name="spName">存储过程名</param>
      /// <param name="parameterValues">分配给存储过程输入参数的对象数组</param>
      /// <returns>返回一个包含结果集的DataSet</returns>
      public static DataSet ExecuteDataset(SqlConnection connection, string spName, params object[] parameterValues)
      {
       if( connection == null ) throw new ArgumentNullException( "connection" );
       if( spName == null || spName.Length == 0 ) throw new ArgumentNullException( "spName" );

       if ((parameterValues != null) && (parameterValues.Length > 0))
       {
        // 比缓存中加载存储过程参数
        SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(connection, spName);

        // 给存储过程参数分配值
        AssignParameterValues(commandParameters, parameterValues);

        return ExecuteDataset(connection, CommandType.StoredProcedure, spName, commandParameters);
       }
       else
       {
        return ExecuteDataset(connection, CommandType.StoredProcedure, spName);
       }
      }

      /// <summary>
      /// 执行指定事务的命令,返回DataSet.
      /// </summary>
      /// <remarks>
      /// 示例: 
      ///  DataSet ds = ExecuteDataset(trans, CommandType.StoredProcedure, "GetOrders");
      /// </remarks>
      /// <param name="transaction">事务</param>
      /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
      /// <param name="commandText">存储过程名或T-SQL语句</param>
      /// <returns>返回一个包含结果集的DataSet</returns>
      public static DataSet ExecuteDataset(SqlTransaction transaction, CommandType commandType, string commandText)
      {
       return ExecuteDataset(transaction, commandType, commandText, (SqlParameter[])null);
      }
           
      /// <summary>
      /// 执行指定事务的命令,指定参数,返回DataSet.
      /// </summary>
      /// <remarks>
      /// 示例: 
      ///  DataSet ds = ExecuteDataset(trans, CommandType.StoredProcedure, "GetOrders", new SqlParameter("@prodid", 24));
      /// </remarks>
      /// <param name="transaction">事务</param>
      /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
      /// <param name="commandText">存储过程名或T-SQL语句</param>
      /// <param name="commandParameters">SqlParamter参数数组</param>
      /// <returns>返回一个包含结果集的DataSet</returns>
      public static DataSet ExecuteDataset(SqlTransaction transaction, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
      {
       if( transaction == null ) throw new ArgumentNullException( "transaction" );
       if( transaction != null && transaction.Connection == null ) throw new ArgumentException( "The transaction was rollbacked or commited, please provide an open transaction.", "transaction" );

       // 预处理
       SqlCommand cmd = new SqlCommand();
       bool mustCloseConnection = false;
       PrepareCommand(cmd, transaction.Connection, transaction, commandType, commandText, commandParameters, out mustCloseConnection );
                   
       // 创建 DataAdapter & DataSet
       using( SqlDataAdapter da = new SqlDataAdapter(cmd) )
       {
        DataSet ds = new DataSet();
        da.Fill(ds);
        cmd.Parameters.Clear();
        return ds;
       }   
      }
           
      /// <summary>
      /// 执行指定事务的命令,指定参数值,返回DataSet.
      /// </summary>
      /// <remarks>
      /// 此方法不提供访问存储过程输入参数和返回值.
      /// 示例.: 
      ///  DataSet ds = ExecuteDataset(trans, "GetOrders", 24, 36);
      /// </remarks>
      /// <param name="transaction">事务</param>
      /// <param name="spName">存储过程名</param>
      /// <param name="parameterValues">分配给存储过程输入参数的对象数组</param>
      /// <returns>返回一个包含结果集的DataSet</returns>
      public static DataSet ExecuteDataset(SqlTransaction transaction, string spName, params object[] parameterValues)
      {
       if( transaction == null ) throw new ArgumentNullException( "transaction" );
       if( transaction != null && transaction.Connection == null ) throw new ArgumentException( "The transaction was rollbacked or commited, please provide an open transaction.", "transaction" );
       if( spName == null || spName.Length == 0 ) throw new ArgumentNullException( "spName" );
               
       if ((parameterValues != null) && (parameterValues.Length > 0))
       {
        // 从缓存中加载存储过程参数
        SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(transaction.Connection, spName);

        // 给存储过程参数分配值
        AssignParameterValues(commandParameters, parameterValues);

        return ExecuteDataset(transaction, CommandType.StoredProcedure, spName, commandParameters);
       }
       else
       {
        return ExecuteDataset(transaction, CommandType.StoredProcedure, spName);
       }
      }

      #endregion ExecuteDataset数据集命令结束
           
      #region ExecuteReader 数据阅读器

      /// <summary>
      /// 枚举,标识数据库连接是由SqlHelper提供还是由调用者提供
      /// </summary>
      private enum SqlConnectionOwnership   
      {
       /// <summary>由SqlHelper提供连接</summary>
       Internal,
       /// <summary>由调用者提供连接</summary>
       External
      }

      /// <summary>
      /// 执行指定数据库连接对象的数据阅读器.
      /// </summary>
      /// <remarks>
      /// 如果是SqlHelper打开连接,当连接关闭DataReader也将关闭.
      /// 如果是调用都打开连接,DataReader由调用都管理.
      /// </remarks>
      /// <param name="connection">一个有效的数据库连接对象</param>
      /// <param name="transaction">一个有效的事务,或者为 'null'</param>
      /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
      /// <param name="commandText">存储过程名或T-SQL语句</param>
      /// <param name="commandParameters">SqlParameters参数数组,如果没有参数则为'null'</param>
      /// <param name="connectionOwnership">标识数据库连接对象是由调用者提供还是由SqlHelper提供</param>
      /// <returns>返回包含结果集的SqlDataReader</returns>
      private static SqlDataReader ExecuteReader(SqlConnection connection, SqlTransaction transaction, CommandType commandType, string commandText, SqlParameter[] commandParameters, SqlConnectionOwnership connectionOwnership)
      {   
       if( connection == null ) throw new ArgumentNullException( "connection" );

       bool mustCloseConnection = false;
       // 创建命令
       SqlCommand cmd = new SqlCommand();
       try
       {
        PrepareCommand(cmd, connection, transaction, commandType, commandText, commandParameters, out mustCloseConnection );
               
        // 创建数据阅读器
        SqlDataReader dataReader;

        if (connectionOwnership == SqlConnectionOwnership.External)
        {
         dataReader = cmd.ExecuteReader();
        }
        else
        {
         dataReader = cmd.ExecuteReader(CommandBehavior.CloseConnection);
        }
               
        // 清除参数,以便再次使用..
        // HACK: There is a problem here, the output parameter values are fletched
        // when the reader is closed, so if the parameters are detached from the command
        // then the SqlReader can磘 set its values.
        // When this happen, the parameters can磘 be used again in other command.
        bool canClear = true;
        foreach(SqlParameter commandParameter in cmd.Parameters)
        {
         if (commandParameter.Direction != ParameterDirection.Input)
          canClear = false;
        }
               
        if (canClear)
        {
         cmd.Parameters.Clear();
        }

        return dataReader;
       }
       catch
       {
        if( mustCloseConnection )
         connection.Close();
        throw;
       }
      }

      /// <summary>
      /// 执行指定数据库连接字符串的数据阅读器.
      /// </summary>
      /// <remarks>
      /// 示例: 
      ///  SqlDataReader dr = ExecuteReader(connString, CommandType.StoredProcedure, "GetOrders");
      /// </remarks>
      /// <param name="connectionString">一个有效的数据库连接字符串</param>
      /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
      /// <param name="commandText">存储过程名或T-SQL语句</param>
      /// <returns>返回包含结果集的SqlDataReader</returns>
      public static SqlDataReader ExecuteReader(string connectionString, CommandType commandType, string commandText)
      {
       return ExecuteReader(connectionString, commandType, commandText, (SqlParameter[])null);
      }

      /// <summary>
      /// 执行指定数据库连接字符串的数据阅读器,指定参数.
      /// </summary>
      /// <remarks>
      /// 示例: 
      ///  SqlDataReader dr = ExecuteReader(connString, CommandType.StoredProcedure, "GetOrders", new SqlParameter("@prodid", 24));
      /// </remarks>
      /// <param name="connectionString">一个有效的数据库连接字符串</param>
      /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
      /// <param name="commandText">存储过程名或T-SQL语句</param>
      /// <param name="commandParameters">SqlParamter参数数组(new SqlParameter("@prodid", 24))</param>
      /// <returns>返回包含结果集的SqlDataReader</returns>
      public static SqlDataReader ExecuteReader(string connectionString, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
      {
       if( connectionString == null || connectionString.Length == 0 ) throw new ArgumentNullException( "connectionString" );
       SqlConnection connection = null;
       try
       {
        connection = new SqlConnection(connectionString);
        connection.Open();

        return ExecuteReader(connection, null, commandType, commandText, commandParameters,SqlConnectionOwnership.Internal);
       }
       catch
       {
        // If we fail to return the SqlDatReader, we need to close the connection ourselves
        if( connection != null ) connection.Close();
        throw;
       }
               
      }

      /// <summary>
      /// 执行指定数据库连接字符串的数据阅读器,指定参数值.
      /// </summary>
      /// <remarks>
      /// 此方法不提供访问存储过程输出参数和返回值参数.
      /// 示例: 
      ///  SqlDataReader dr = ExecuteReader(connString, "GetOrders", 24, 36);
      /// </remarks>
      /// <param name="connectionString">一个有效的数据库连接字符串</param>
      /// <param name="spName">存储过程名</param>
      /// <param name="parameterValues">分配给存储过程输入参数的对象数组</param>
      /// <returns>返回包含结果集的SqlDataReader</returns>
      public static SqlDataReader ExecuteReader(string connectionString, string spName, params object[] parameterValues)
      {
       if( connectionString == null || connectionString.Length == 0 ) throw new ArgumentNullException( "connectionString" );
       if( spName == null || spName.Length == 0 ) throw new ArgumentNullException( "spName" );
               
       if ((parameterValues != null) && (parameterValues.Length > 0))
       {
        SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(connectionString, spName);

        AssignParameterValues(commandParameters, parameterValues);

        return ExecuteReader(connectionString, CommandType.StoredProcedure, spName, commandParameters);
       }
       else
       {
        return ExecuteReader(connectionString, CommandType.StoredProcedure, spName);
       }
      }

      /// <summary>
      /// 执行指定数据库连接对象的数据阅读器.
      /// </summary>
      /// <remarks>
      /// 示例: 
      ///  SqlDataReader dr = ExecuteReader(conn, CommandType.StoredProcedure, "GetOrders");
      /// </remarks>
      /// <param name="connection">一个有效的数据库连接对象</param>
      /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
      /// <param name="commandText">存储过程名或T-SQL语句</param>
      /// <returns>返回包含结果集的SqlDataReader</returns>
      public static SqlDataReader ExecuteReader(SqlConnection connection, CommandType commandType, string commandText)
      {
       return ExecuteReader(connection, commandType, commandText, (SqlParameter[])null);
      }

      /// <summary>
      /// [调用者方式]执行指定数据库连接对象的数据阅读器,指定参数.
      /// </summary>
      /// <remarks>
      /// 示例: 
      ///  SqlDataReader dr = ExecuteReader(conn, CommandType.StoredProcedure, "GetOrders", new SqlParameter("@prodid", 24));
      /// </remarks>
      /// <param name="connection">一个有效的数据库连接对象</param>
      /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
      /// <param name="commandText">命令类型 (存储过程,命令文本或其它)</param>
      /// <param name="commandParameters">SqlParamter参数数组</param>
      /// <returns>返回包含结果集的SqlDataReader</returns>
      public static SqlDataReader ExecuteReader(SqlConnection connection, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
      {
       return ExecuteReader(connection, (SqlTransaction)null, commandType, commandText, commandParameters, SqlConnectionOwnership.External);
      }

      /// <summary>
      /// [调用者方式]执行指定数据库连接对象的数据阅读器,指定参数值.
      /// </summary>
      /// <remarks>
      /// 此方法不提供访问存储过程输出参数和返回值参数.
      /// 示例: 
      ///  SqlDataReader dr = ExecuteReader(conn, "GetOrders", 24, 36);
      /// </remarks>
      /// <param name="connection">一个有效的数据库连接对象</param>
      /// <param name="spName">T存储过程名</param>
      /// <param name="parameterValues">分配给存储过程输入参数的对象数组</param>
      /// <returns>返回包含结果集的SqlDataReader</returns>
      public static SqlDataReader ExecuteReader(SqlConnection connection, string spName, params object[] parameterValues)
      {
       if( connection == null ) throw new ArgumentNullException( "connection" );
       if( spName == null || spName.Length == 0 ) throw new ArgumentNullException( "spName" );

       if ((parameterValues != null) && (parameterValues.Length > 0))
       {
        SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(connection, spName);

        AssignParameterValues(commandParameters, parameterValues);

        return ExecuteReader(connection, CommandType.StoredProcedure, spName, commandParameters);
       }
       else
       {
        return ExecuteReader(connection, CommandType.StoredProcedure, spName);
       }
      }

      /// <summary>
      /// [调用者方式]执行指定数据库事务的数据阅读器,指定参数值.
      /// </summary>
      /// <remarks>
      /// 示例: 
      ///  SqlDataReader dr = ExecuteReader(trans, CommandType.StoredProcedure, "GetOrders");
      /// </remarks>
      /// <param name="transaction">一个有效的连接事务</param>
      /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
      /// <param name="commandText">存储过程名称或T-SQL语句</param>
      /// <returns>返回包含结果集的SqlDataReader</returns>
      public static SqlDataReader ExecuteReader(SqlTransaction transaction, CommandType commandType, string commandText)
      {
       return ExecuteReader(transaction, commandType, commandText, (SqlParameter[])null);
      }

      /// <summary>
      /// [调用者方式]执行指定数据库事务的数据阅读器,指定参数.
      /// </summary>
      /// <remarks>
      /// 示例: 
      ///   SqlDataReader dr = ExecuteReader(trans, CommandType.StoredProcedure, "GetOrders", new SqlParameter("@prodid", 24));
      /// </remarks>
      /// <param name="transaction">一个有效的连接事务</param>
      /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
      /// <param name="commandText">存储过程名称或T-SQL语句</param>
      /// <param name="commandParameters">分配给命令的SqlParamter参数数组</param>
      /// <returns>返回包含结果集的SqlDataReader</returns>
      public static SqlDataReader ExecuteReader(SqlTransaction transaction, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
      {
       if( transaction == null ) throw new ArgumentNullException( "transaction" );
       if( transaction != null && transaction.Connection == null ) throw new ArgumentException( "The transaction was rollbacked or commited, please provide an open transaction.", "transaction" );

       return ExecuteReader(transaction.Connection, transaction, commandType, commandText, commandParameters, SqlConnectionOwnership.External);
      }

      /// <summary>
      /// [调用者方式]执行指定数据库事务的数据阅读器,指定参数值.
      /// </summary>
      /// <remarks>
      /// 此方法不提供访问存储过程输出参数和返回值参数.
      ///
      /// 示例: 
      ///  SqlDataReader dr = ExecuteReader(trans, "GetOrders", 24, 36);
      /// </remarks>
      /// <param name="transaction">一个有效的连接事务</param>
      /// <param name="spName">存储过程名称</param>
      /// <param name="parameterValues">分配给存储过程输入参数的对象数组</param>
      /// <returns>返回包含结果集的SqlDataReader</returns>
      public static SqlDataReader ExecuteReader(SqlTransaction transaction, string spName, params object[] parameterValues)
      {
       if( transaction == null ) throw new ArgumentNullException( "transaction" );
       if( transaction != null && transaction.Connection == null ) throw new ArgumentException( "The transaction was rollbacked or commited, please provide an open transaction.", "transaction" );
       if( spName == null || spName.Length == 0 ) throw new ArgumentNullException( "spName" );

       // 如果有参数值
       if ((parameterValues != null) && (parameterValues.Length > 0))
       {
        SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(transaction.Connection, spName);

        AssignParameterValues(commandParameters, parameterValues);

        return ExecuteReader(transaction, CommandType.StoredProcedure, spName, commandParameters);
       }
       else
       {
        // 没有参数值
        return ExecuteReader(transaction, CommandType.StoredProcedure, spName);
       }
      }

      #endregion ExecuteReader数据阅读器

      #region ExecuteScalar 返回结果集中的第一行第一列
           
      /// <summary>
      /// 执行指定数据库连接字符串的命令,返回结果集中的第一行第一列.
      /// </summary>
      /// <remarks>
      /// 示例: 
      ///  int orderCount = (int)ExecuteScalar(connString, CommandType.StoredProcedure, "GetOrderCount");
      /// </remarks>
      /// <param name="connectionString">一个有效的数据库连接字符串</param>
      /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
      /// <param name="commandText">存储过程名称或T-SQL语句</param>
      /// <returns>返回结果集中的第一行第一列</returns>
      public static object ExecuteScalar(string connectionString, CommandType commandType, string commandText)
      {
       // 执行参数为空的方法
       return ExecuteScalar(connectionString, commandType, commandText, (SqlParameter[])null);
      }

      /// <summary>
      /// 执行指定数据库连接字符串的命令,指定参数,返回结果集中的第一行第一列.
      /// </summary>
      /// <remarks>
      /// 示例: 
      ///  int orderCount = (int)ExecuteScalar(connString, CommandType.StoredProcedure, "GetOrderCount", new SqlParameter("@prodid", 24));
      /// </remarks>
      /// <param name="connectionString">一个有效的数据库连接字符串</param>
      /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
      /// <param name="commandText">存储过程名称或T-SQL语句</param>
      /// <param name="commandParameters">分配给命令的SqlParamter参数数组</param>
      /// <returns>返回结果集中的第一行第一列</returns>
      public static object ExecuteScalar(string connectionString, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
      {
       if( connectionString == null || connectionString.Length == 0 ) throw new ArgumentNullException( "connectionString" );
       // 创建并打开数据库连接对象,操作完成释放对象.
       using (SqlConnection connection = new SqlConnection(connectionString))
       {
        connection.Open();

        // 调用指定数据库连接字符串重载方法.
        return ExecuteScalar(connection, commandType, commandText, commandParameters);
       }
      }

      /// <summary>
      /// 执行指定数据库连接字符串的命令,指定参数值,返回结果集中的第一行第一列.
      /// </summary>
      /// <remarks>
      /// 此方法不提供访问存储过程输出参数和返回值参数.
      ///
      /// 示例: 
      ///  int orderCount = (int)ExecuteScalar(connString, "GetOrderCount", 24, 36);
      /// </remarks>
      /// <param name="connectionString">一个有效的数据库连接字符串</param>
      /// <param name="spName">存储过程名称</param>
      /// <param name="parameterValues">分配给存储过程输入参数的对象数组</param>
      /// <returns>返回结果集中的第一行第一列</returns>
      public static object ExecuteScalar(string connectionString, string spName, params object[] parameterValues)
      {
       if( connectionString == null || connectionString.Length == 0 ) throw new ArgumentNullException( "connectionString" );
       if( spName == null || spName.Length == 0 ) throw new ArgumentNullException( "spName" );
               
       // 如果有参数值
       if ((parameterValues != null) && (parameterValues.Length > 0))
       {
        // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
        SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(connectionString, spName);

        // 给存储过程参数赋值
        AssignParameterValues(commandParameters, parameterValues);

        // 调用重载方法
        return ExecuteScalar(connectionString, CommandType.StoredProcedure, spName, commandParameters);
       }
       else
       {
        // 没有参数值
        return ExecuteScalar(connectionString, CommandType.StoredProcedure, spName);
       }
      }

      /// <summary>
      /// 执行指定数据库连接对象的命令,返回结果集中的第一行第一列.
      /// </summary>
      /// <remarks>
      /// 示例: 
      ///  int orderCount = (int)ExecuteScalar(conn, CommandType.StoredProcedure, "GetOrderCount");
      /// </remarks>
      /// <param name="connection">一个有效的数据库连接对象</param>
      /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
      /// <param name="commandText">存储过程名称或T-SQL语句</param>
      /// <returns>返回结果集中的第一行第一列</returns>
      public static object ExecuteScalar(SqlConnection connection, CommandType commandType, string commandText)
      {
       // 执行参数为空的方法
       return ExecuteScalar(connection, commandType, commandText, (SqlParameter[])null);
      }

      /// <summary>
      /// 执行指定数据库连接对象的命令,指定参数,返回结果集中的第一行第一列.
      /// </summary>
      /// <remarks>
      /// 示例: 
      ///  int orderCount = (int)ExecuteScalar(conn, CommandType.StoredProcedure, "GetOrderCount", new SqlParameter("@prodid", 24));
      /// </remarks>
      /// <param name="connection">一个有效的数据库连接对象</param>
      /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
      /// <param name="commandText">存储过程名称或T-SQL语句</param>
      /// <param name="commandParameters">分配给命令的SqlParamter参数数组</param>
      /// <returns>返回结果集中的第一行第一列</returns>
      public static object ExecuteScalar(SqlConnection connection, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
      {
       if( connection == null ) throw new ArgumentNullException( "connection" );

       // 创建SqlCommand命令,并进行预处理
       SqlCommand cmd = new SqlCommand();

       bool mustCloseConnection = false;
       PrepareCommand(cmd, connection, (SqlTransaction)null, commandType, commandText, commandParameters, out mustCloseConnection );
                   
       // 执行SqlCommand命令,并返回结果.
       object retval = cmd.ExecuteScalar();
                   
       // 清除参数,以便再次使用.
       cmd.Parameters.Clear();

       if( mustCloseConnection )
        connection.Close();

       return retval;
      }

      /// <summary>
      /// 执行指定数据库连接对象的命令,指定参数值,返回结果集中的第一行第一列.
      /// </summary>
      /// <remarks>
      /// 此方法不提供访问存储过程输出参数和返回值参数.
      ///
      /// 示例: 
      ///  int orderCount = (int)ExecuteScalar(conn, "GetOrderCount", 24, 36);
      /// </remarks>
      /// <param name="connection">一个有效的数据库连接对象</param>
      /// <param name="spName">存储过程名称</param>
      /// <param name="parameterValues">分配给存储过程输入参数的对象数组</param>
      /// <returns>返回结果集中的第一行第一列</returns>
      public static object ExecuteScalar(SqlConnection connection, string spName, params object[] parameterValues)
      {
       if( connection == null ) throw new ArgumentNullException( "connection" );
       if( spName == null || spName.Length == 0 ) throw new ArgumentNullException( "spName" );

       // 如果有参数值
       if ((parameterValues != null) && (parameterValues.Length > 0))
       {
        // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
        SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(connection, spName);

        // 给存储过程参数赋值
        AssignParameterValues(commandParameters, parameterValues);

        // 调用重载方法
        return ExecuteScalar(connection, CommandType.StoredProcedure, spName, commandParameters);
       }
       else
       {
        // 没有参数值
        return ExecuteScalar(connection, CommandType.StoredProcedure, spName);
       }
      }

      /// <summary>
      /// 执行指定数据库事务的命令,返回结果集中的第一行第一列.
      /// </summary>
      /// <remarks>
      /// 示例: 
      ///  int orderCount = (int)ExecuteScalar(trans, CommandType.StoredProcedure, "GetOrderCount");
      /// </remarks>
      /// <param name="transaction">一个有效的连接事务</param>
      /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
      /// <param name="commandText">存储过程名称或T-SQL语句</param>
      /// <returns>返回结果集中的第一行第一列</returns>
      public static object ExecuteScalar(SqlTransaction transaction, CommandType commandType, string commandText)
      {
       // 执行参数为空的方法
       return ExecuteScalar(transaction, commandType, commandText, (SqlParameter[])null);
      }

      /// <summary>
      /// 执行指定数据库事务的命令,指定参数,返回结果集中的第一行第一列.
      /// </summary>
      /// <remarks>
      /// 示例: 
      ///  int orderCount = (int)ExecuteScalar(trans, CommandType.StoredProcedure, "GetOrderCount", new SqlParameter("@prodid", 24));
      /// </remarks>
      /// <param name="transaction">一个有效的连接事务</param>
      /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
      /// <param name="commandText">存储过程名称或T-SQL语句</param>
      /// <param name="commandParameters">分配给命令的SqlParamter参数数组</param>
      /// <returns>返回结果集中的第一行第一列</returns>
      public static object ExecuteScalar(SqlTransaction transaction, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
      {
       if( transaction == null ) throw new ArgumentNullException( "transaction" );
       if( transaction != null && transaction.Connection == null ) throw new ArgumentException( "The transaction was rollbacked or commited, please provide an open transaction.", "transaction" );

       // 创建SqlCommand命令,并进行预处理
       SqlCommand cmd = new SqlCommand();
       bool mustCloseConnection = false;
       PrepareCommand(cmd, transaction.Connection, transaction, commandType, commandText, commandParameters, out mustCloseConnection );
                   
       // 执行SqlCommand命令,并返回结果.
       object retval = cmd.ExecuteScalar();
                   
       // 清除参数,以便再次使用.
       cmd.Parameters.Clear();
       return retval;
      }

      /// <summary>
      /// 执行指定数据库事务的命令,指定参数值,返回结果集中的第一行第一列.
      /// </summary>
      /// <remarks>
      /// 此方法不提供访问存储过程输出参数和返回值参数.
      ///
      /// 示例: 
      ///  int orderCount = (int)ExecuteScalar(trans, "GetOrderCount", 24, 36);
      /// </remarks>
      /// <param name="transaction">一个有效的连接事务</param>
      /// <param name="spName">存储过程名称</param>
      /// <param name="parameterValues">分配给存储过程输入参数的对象数组</param>
      /// <returns>返回结果集中的第一行第一列</returns>
      public static object ExecuteScalar(SqlTransaction transaction, string spName, params object[] parameterValues)
      {
       if( transaction == null ) throw new ArgumentNullException( "transaction" );
       if( transaction != null && transaction.Connection == null ) throw new ArgumentException( "The transaction was rollbacked or commited, please provide an open transaction.", "transaction" );
       if( spName == null || spName.Length == 0 ) throw new ArgumentNullException( "spName" );

       // 如果有参数值
       if ((parameterValues != null) && (parameterValues.Length > 0))
       {
        // PPull the parameters for this stored procedure from the parameter cache ()
        SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(transaction.Connection, spName);

        // 给存储过程参数赋值
        AssignParameterValues(commandParameters, parameterValues);

        // 调用重载方法
        return ExecuteScalar(transaction, CommandType.StoredProcedure, spName, commandParameters);
       }
       else
       {
        // 没有参数值
        return ExecuteScalar(transaction, CommandType.StoredProcedure, spName);
       }
      }

      #endregion ExecuteScalar   

      #region ExecuteXmlReader XML阅读器
      /// <summary>
      /// 执行指定数据库连接对象的SqlCommand命令,并产生一个XmlReader对象做为结果集返回.
      /// </summary>
      /// <remarks>
      /// 示例: 
      ///  XmlReader r = ExecuteXmlReader(conn, CommandType.StoredProcedure, "GetOrders");
      /// </remarks>
      /// <param name="connection">一个有效的数据库连接对象</param>
      /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
      /// <param name="commandText">存储过程名称或T-SQL语句 using "FOR XML AUTO"</param>
      /// <returns>返回XmlReader结果集对象.</returns>
      public static XmlReader ExecuteXmlReader(SqlConnection connection, CommandType commandType, string commandText)
      {
       // 执行参数为空的方法
       return ExecuteXmlReader(connection, commandType, commandText, (SqlParameter[])null);
      }

      /// <summary>
      /// 执行指定数据库连接对象的SqlCommand命令,并产生一个XmlReader对象做为结果集返回,指定参数.
      /// </summary>
      /// <remarks>
      /// 示例: 
      ///  XmlReader r = ExecuteXmlReader(conn, CommandType.StoredProcedure, "GetOrders", new SqlParameter("@prodid", 24));
      /// </remarks>
      /// <param name="connection">一个有效的数据库连接对象</param>
      /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
      /// <param name="commandText">存储过程名称或T-SQL语句 using "FOR XML AUTO"</param>
      /// <param name="commandParameters">分配给命令的SqlParamter参数数组</param>
      /// <returns>返回XmlReader结果集对象.</returns>
      public static XmlReader ExecuteXmlReader(SqlConnection connection, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
      {
       if( connection == null ) throw new ArgumentNullException( "connection" );

       bool mustCloseConnection = false;
       // 创建SqlCommand命令,并进行预处理
       SqlCommand cmd = new SqlCommand();
       try
       {
        PrepareCommand(cmd, connection, (SqlTransaction)null, commandType, commandText, commandParameters, out mustCloseConnection );
               
        // 执行命令
        XmlReader retval = cmd.ExecuteXmlReader();
               
        // 清除参数,以便再次使用.
        cmd.Parameters.Clear();

        return retval;
       }
       catch
       {   
        if( mustCloseConnection )
         connection.Close();
        throw;
       }
      }

      /// <summary>
      /// 执行指定数据库连接对象的SqlCommand命令,并产生一个XmlReader对象做为结果集返回,指定参数值.
      /// </summary>
      /// <remarks>
      /// 此方法不提供访问存储过程输出参数和返回值参数.
      ///
      /// 示例: 
      ///  XmlReader r = ExecuteXmlReader(conn, "GetOrders", 24, 36);
      /// </remarks>
      /// <param name="connection">一个有效的数据库连接对象</param>
      /// <param name="spName">存储过程名称 using "FOR XML AUTO"</param>
      /// <param name="parameterValues">分配给存储过程输入参数的对象数组</param>
      /// <returns>返回XmlReader结果集对象.</returns>
      public static XmlReader ExecuteXmlReader(SqlConnection connection, string spName, params object[] parameterValues)
      {
       if( connection == null ) throw new ArgumentNullException( "connection" );
       if( spName == null || spName.Length == 0 ) throw new ArgumentNullException( "spName" );

       // 如果有参数值
       if ((parameterValues != null) && (parameterValues.Length > 0))
       {
        // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
        SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(connection, spName);

        // 给存储过程参数赋值
        AssignParameterValues(commandParameters, parameterValues);

        // 调用重载方法
        return ExecuteXmlReader(connection, CommandType.StoredProcedure, spName, commandParameters);
       }
       else
       {
        // 没有参数值
        return ExecuteXmlReader(connection, CommandType.StoredProcedure, spName);
       }
      }

      /// <summary>
      /// 执行指定数据库事务的SqlCommand命令,并产生一个XmlReader对象做为结果集返回.
      /// </summary>
      /// <remarks>
      /// 示例: 
      ///  XmlReader r = ExecuteXmlReader(trans, CommandType.StoredProcedure, "GetOrders");
      /// </remarks>
      /// <param name="transaction">一个有效的连接事务</param>
      /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
      /// <param name="commandText">存储过程名称或T-SQL语句 using "FOR XML AUTO"</param>
      /// <returns>返回XmlReader结果集对象.</returns>
      public static XmlReader ExecuteXmlReader(SqlTransaction transaction, CommandType commandType, string commandText)
      {
       // 执行参数为空的方法
       return ExecuteXmlReader(transaction, commandType, commandText, (SqlParameter[])null);
      }

      /// <summary>
      /// 执行指定数据库事务的SqlCommand命令,并产生一个XmlReader对象做为结果集返回,指定参数.
      /// </summary>
      /// <remarks>
      /// 示例: 
      ///  XmlReader r = ExecuteXmlReader(trans, CommandType.StoredProcedure, "GetOrders", new SqlParameter("@prodid", 24));
      /// </remarks>
      /// <param name="transaction">一个有效的连接事务</param>
      /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
      /// <param name="commandText">存储过程名称或T-SQL语句 using "FOR XML AUTO"</param>
      /// <param name="commandParameters">分配给命令的SqlParamter参数数组</param>
      /// <returns>返回XmlReader结果集对象.</returns>
      public static XmlReader ExecuteXmlReader(SqlTransaction transaction, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
      {
       if( transaction == null ) throw new ArgumentNullException( "transaction" );
       if( transaction != null && transaction.Connection == null ) throw new ArgumentException( "The transaction was rollbacked or commited, please provide an open transaction.", "transaction" );

       // 创建SqlCommand命令,并进行预处理
       SqlCommand cmd = new SqlCommand();
       bool mustCloseConnection = false;
       PrepareCommand(cmd, transaction.Connection, transaction, commandType, commandText, commandParameters, out mustCloseConnection );
               
       // 执行命令
       XmlReader retval = cmd.ExecuteXmlReader();
               
       // 清除参数,以便再次使用.
       cmd.Parameters.Clear();
       return retval;           
      }

      /// <summary>
      /// 执行指定数据库事务的SqlCommand命令,并产生一个XmlReader对象做为结果集返回,指定参数值.
      /// </summary>
      /// <remarks>
      /// 此方法不提供访问存储过程输出参数和返回值参数.
      ///
      /// 示例: 
      ///  XmlReader r = ExecuteXmlReader(trans, "GetOrders", 24, 36);
      /// </remarks>
      /// <param name="transaction">一个有效的连接事务</param>
      /// <param name="spName">存储过程名称</param>
      /// <param name="parameterValues">分配给存储过程输入参数的对象数组</param>
      /// <returns>返回一个包含结果集的DataSet.</returns>
      public static XmlReader ExecuteXmlReader(SqlTransaction transaction, string spName, params object[] parameterValues)
      {
       if( transaction == null ) throw new ArgumentNullException( "transaction" );
       if( transaction != null && transaction.Connection == null ) throw new ArgumentException( "The transaction was rollbacked or commited, please provide an open transaction.", "transaction" );
       if( spName == null || spName.Length == 0 ) throw new ArgumentNullException( "spName" );

       // 如果有参数值
       if ((parameterValues != null) && (parameterValues.Length > 0))
       {
        // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
        SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(transaction.Connection, spName);

        // 给存储过程参数赋值
        AssignParameterValues(commandParameters, parameterValues);

        // 调用重载方法
        return ExecuteXmlReader(transaction, CommandType.StoredProcedure, spName, commandParameters);
       }
       else
       {
        // 没有参数值
        return ExecuteXmlReader(transaction, CommandType.StoredProcedure, spName);
       }
      }

      #endregion ExecuteXmlReader 阅读器结束

      #region FillDataset 填充数据集
      /// <summary>
      /// 执行指定数据库连接字符串的命令,映射数据表并填充数据集.
      /// </summary>
      /// <remarks>
      /// 示例: 
      ///  FillDataset(connString, CommandType.StoredProcedure, "GetOrders", ds, new string[] {"orders"});
      /// </remarks>
      /// <param name="connectionString">一个有效的数据库连接字符串</param>
      /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
      /// <param name="commandText">存储过程名称或T-SQL语句</param>
      /// <param name="dataSet">要填充结果集的DataSet实例</param>
      /// <param name="tableNames">表映射的数据表数组
      /// 用户定义的表名 (可有是实际的表名.)</param>
      public static void FillDataset(string connectionString, CommandType commandType, string commandText, DataSet dataSet, string[] tableNames)
      {
       if( connectionString == null || connectionString.Length == 0 ) throw new ArgumentNullException( "connectionString" );
       if( dataSet == null ) throw new ArgumentNullException( "dataSet" );
               
       // 创建并打开数据库连接对象,操作完成释放对象.
       using (SqlConnection connection = new SqlConnection(connectionString))
       {
        connection.Open();

        // 调用指定数据库连接字符串重载方法.
        FillDataset(connection, commandType, commandText, dataSet, tableNames);
       }
      }

      /// <summary>
      /// 执行指定数据库连接字符串的命令,映射数据表并填充数据集.指定命令参数.
      /// </summary>
      /// <remarks>
      /// 示例: 
      ///  FillDataset(connString, CommandType.StoredProcedure, "GetOrders", ds, new string[] {"orders"}, new SqlParameter("@prodid", 24));
      /// </remarks>
      /// <param name="connectionString">一个有效的数据库连接字符串</param>
      /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
      /// <param name="commandText">存储过程名称或T-SQL语句</param>
      /// <param name="commandParameters">分配给命令的SqlParamter参数数组</param>
      /// <param name="dataSet">要填充结果集的DataSet实例</param>
      /// <param name="tableNames">表映射的数据表数组
      /// 用户定义的表名 (可有是实际的表名.)
      /// </param>
      public static void FillDataset(string connectionString, CommandType commandType,
       string commandText, DataSet dataSet, string[] tableNames,
       params SqlParameter[] commandParameters)
      {
       if( connectionString == null || connectionString.Length == 0 ) throw new ArgumentNullException( "connectionString" );
       if( dataSet == null ) throw new ArgumentNullException( "dataSet" );
       // 创建并打开数据库连接对象,操作完成释放对象.
       using (SqlConnection connection = new SqlConnection(connectionString))
       {
        connection.Open();

        // 调用指定数据库连接字符串重载方法.
        FillDataset(connection, commandType, commandText, dataSet, tableNames, commandParameters);
       }
      }

      /// <summary>
      /// 执行指定数据库连接字符串的命令,映射数据表并填充数据集,指定存储过程参数值.
      /// </summary>
      /// <remarks>
      /// 此方法不提供访问存储过程输出参数和返回值参数.
      ///
      /// 示例: 
      ///  FillDataset(connString, CommandType.StoredProcedure, "GetOrders", ds, new string[] {"orders"}, 24);
      /// </remarks>
      /// <param name="connectionString">一个有效的数据库连接字符串</param>
      /// <param name="spName">存储过程名称</param>
      /// <param name="dataSet">要填充结果集的DataSet实例</param>
      /// <param name="tableNames">表映射的数据表数组
      /// 用户定义的表名 (可有是实际的表名.)
      /// </param>   
      /// <param name="parameterValues">分配给存储过程输入参数的对象数组</param>
      public static void FillDataset(string connectionString, string spName,
       DataSet dataSet, string[] tableNames,
       params object[] parameterValues)
      {
       if( connectionString == null || connectionString.Length == 0 ) throw new ArgumentNullException( "connectionString" );
       if( dataSet == null ) throw new ArgumentNullException( "dataSet" );
       // 创建并打开数据库连接对象,操作完成释放对象.
       using (SqlConnection connection = new SqlConnection(connectionString))
       {
        connection.Open();

        // 调用指定数据库连接字符串重载方法.
        FillDataset (connection, spName, dataSet, tableNames, parameterValues);
       }
      }

      /// <summary>
      /// 执行指定数据库连接对象的命令,映射数据表并填充数据集.
      /// </summary>
      /// <remarks>
      /// 示例: 
      ///  FillDataset(conn, CommandType.StoredProcedure, "GetOrders", ds, new string[] {"orders"});
      /// </remarks>
      /// <param name="connection">一个有效的数据库连接对象</param>
      /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
      /// <param name="commandText">存储过程名称或T-SQL语句</param>
      /// <param name="dataSet">要填充结果集的DataSet实例</param>
      /// <param name="tableNames">表映射的数据表数组
      /// 用户定义的表名 (可有是实际的表名.)
      /// </param>   
      public static void FillDataset(SqlConnection connection, CommandType commandType,
       string commandText, DataSet dataSet, string[] tableNames)
      {
       FillDataset(connection, commandType, commandText, dataSet, tableNames, null);
      }

      /// <summary>
      /// 执行指定数据库连接对象的命令,映射数据表并填充数据集,指定参数.
      /// </summary>
      /// <remarks>
      /// 示例: 
      ///  FillDataset(conn, CommandType.StoredProcedure, "GetOrders", ds, new string[] {"orders"}, new SqlParameter("@prodid", 24));
      /// </remarks>
      /// <param name="connection">一个有效的数据库连接对象</param>
      /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
      /// <param name="commandText">存储过程名称或T-SQL语句</param>
      /// <param name="dataSet">要填充结果集的DataSet实例</param>
      /// <param name="tableNames">表映射的数据表数组
      /// 用户定义的表名 (可有是实际的表名.)
      /// </param>
      /// <param name="commandParameters">分配给命令的SqlParamter参数数组</param>
      public static void FillDataset(SqlConnection connection, CommandType commandType,
       string commandText, DataSet dataSet, string[] tableNames,
       params SqlParameter[] commandParameters)
      {
       FillDataset(connection, null, commandType, commandText, dataSet, tableNames, commandParameters);
      }

      /// <summary>
      /// 执行指定数据库连接对象的命令,映射数据表并填充数据集,指定存储过程参数值.
      /// </summary>
      /// <remarks>
      /// 此方法不提供访问存储过程输出参数和返回值参数.
      ///
      /// 示例: 
      ///  FillDataset(conn, "GetOrders", ds, new string[] {"orders"}, 24, 36);
      /// </remarks>
      /// <param name="connection">一个有效的数据库连接对象</param>
      /// <param name="spName">存储过程名称</param>
      /// <param name="dataSet">要填充结果集的DataSet实例</param>
      /// <param name="tableNames">表映射的数据表数组
      /// 用户定义的表名 (可有是实际的表名.)
      /// </param>
      /// <param name="parameterValues">分配给存储过程输入参数的对象数组</param>
      public static void FillDataset(SqlConnection connection, string spName,
       DataSet dataSet, string[] tableNames,
       params object[] parameterValues)
      {
       if ( connection == null ) throw new ArgumentNullException( "connection" );
       if (dataSet == null ) throw new ArgumentNullException( "dataSet" );
       if( spName == null || spName.Length == 0 ) throw new ArgumentNullException( "spName" );

       // 如果有参数值
       if ((parameterValues != null) && (parameterValues.Length > 0))
       {
        // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
        SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(connection, spName);

        // 给存储过程参数赋值
        AssignParameterValues(commandParameters, parameterValues);

        // 调用重载方法
        FillDataset(connection, CommandType.StoredProcedure, spName, dataSet, tableNames, commandParameters);
       }
       else
       {
        // 没有参数值
        FillDataset(connection, CommandType.StoredProcedure, spName, dataSet, tableNames);
       }   
      }

      /// <summary>
      /// 执行指定数据库事务的命令,映射数据表并填充数据集.
      /// </summary>
      /// <remarks>
      /// 示例: 
      ///  FillDataset(trans, CommandType.StoredProcedure, "GetOrders", ds, new string[] {"orders"});
      /// </remarks>
      /// <param name="transaction">一个有效的连接事务</param>
      /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
      /// <param name="commandText">存储过程名称或T-SQL语句</param>
      /// <param name="dataSet">要填充结果集的DataSet实例</param>
      /// <param name="tableNames">表映射的数据表数组
      /// 用户定义的表名 (可有是实际的表名.)
      /// </param>
      public static void FillDataset(SqlTransaction transaction, CommandType commandType,
       string commandText,
       DataSet dataSet, string[] tableNames)
      {
       FillDataset (transaction, commandType, commandText, dataSet, tableNames, null);   
      }

      /// <summary>
      /// 执行指定数据库事务的命令,映射数据表并填充数据集,指定参数.
      /// </summary>
      /// <remarks>
      /// 示例: 
      ///  FillDataset(trans, CommandType.StoredProcedure, "GetOrders", ds, new string[] {"orders"}, new SqlParameter("@prodid", 24));
      /// </remarks>
      /// <param name="transaction">一个有效的连接事务</param>
      /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
      /// <param name="commandText">存储过程名称或T-SQL语句</param>
      /// <param name="dataSet">要填充结果集的DataSet实例</param>
      /// <param name="tableNames">表映射的数据表数组
      /// 用户定义的表名 (可有是实际的表名.)
      /// </param>
      /// <param name="commandParameters">分配给命令的SqlParamter参数数组</param>
      public static void FillDataset(SqlTransaction transaction, CommandType commandType,
       string commandText, DataSet dataSet, string[] tableNames,
       params SqlParameter[] commandParameters)
      {
       FillDataset(transaction.Connection, transaction, commandType, commandText, dataSet, tableNames, commandParameters);
      }

      /// <summary>
      /// 执行指定数据库事务的命令,映射数据表并填充数据集,指定存储过程参数值.
      /// </summary>
      /// <remarks>
      /// 此方法不提供访问存储过程输出参数和返回值参数.
      ///
      /// 示例: 
      ///  FillDataset(trans, "GetOrders", ds, new string[]{"orders"}, 24, 36);
      /// </remarks>
      /// <param name="transaction">一个有效的连接事务</param>
      /// <param name="spName">存储过程名称</param>
      /// <param name="dataSet">要填充结果集的DataSet实例</param>
      /// <param name="tableNames">表映射的数据表数组
      /// 用户定义的表名 (可有是实际的表名.)
      /// </param>
      /// <param name="parameterValues">分配给存储过程输入参数的对象数组</param>
      public static void FillDataset(SqlTransaction transaction, string spName,
       DataSet dataSet, string[] tableNames,
       params object[] parameterValues)
      {
       if( transaction == null ) throw new ArgumentNullException( "transaction" );
       if( transaction != null && transaction.Connection == null ) throw new ArgumentException( "The transaction was rollbacked or commited, please provide an open transaction.", "transaction" );
       if( dataSet == null ) throw new ArgumentNullException( "dataSet" );
       if( spName == null || spName.Length == 0 ) throw new ArgumentNullException( "spName" );

       // 如果有参数值
       if ((parameterValues != null) && (parameterValues.Length > 0))
       {
        // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
        SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(transaction.Connection, spName);

        // 给存储过程参数赋值
        AssignParameterValues(commandParameters, parameterValues);

        // 调用重载方法
        FillDataset(transaction, CommandType.StoredProcedure, spName, dataSet, tableNames, commandParameters);
       }
       else
       {
        // 没有参数值
        FillDataset(transaction, CommandType.StoredProcedure, spName, dataSet, tableNames);
       }   
      }

      /// <summary>
      /// [私有方法][内部调用]执行指定数据库连接对象/事务的命令,映射数据表并填充数据集,DataSet/TableNames/SqlParameters.
      /// </summary>
      /// <remarks>
      /// 示例: 
      ///  FillDataset(conn, trans, CommandType.StoredProcedure, "GetOrders", ds, new string[] {"orders"}, new SqlParameter("@prodid", 24));
      /// </remarks>
      /// <param name="connection">一个有效的数据库连接对象</param>
      /// <param name="transaction">一个有效的连接事务</param>
      /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
      /// <param name="commandText">存储过程名称或T-SQL语句</param>
      /// <param name="dataSet">要填充结果集的DataSet实例</param>
      /// <param name="tableNames">表映射的数据表数组
      /// 用户定义的表名 (可有是实际的表名.)
      /// </param>
      /// <param name="commandParameters">分配给命令的SqlParamter参数数组</param>
      private static void FillDataset(SqlConnection connection, SqlTransaction transaction, CommandType commandType,
       string commandText, DataSet dataSet, string[] tableNames,
       params SqlParameter[] commandParameters)
      {
       if( connection == null ) throw new ArgumentNullException( "connection" );
       if( dataSet == null ) throw new ArgumentNullException( "dataSet" );

       // 创建SqlCommand命令,并进行预处理
       SqlCommand command = new SqlCommand();
       bool mustCloseConnection = false;
       PrepareCommand(command, connection, transaction, commandType, commandText, commandParameters, out mustCloseConnection );
                   
       // 执行命令
       using( SqlDataAdapter dataAdapter = new SqlDataAdapter(command) )
       {
                   
        // 追加表映射
        if (tableNames != null && tableNames.Length > 0)
        {
         string tableName = "Table";
         for (int index=0; index < tableNames.Length; index++)
         {
          if( tableNames[index] == null || tableNames[index].Length == 0 ) throw new ArgumentException( "The tableNames parameter must contain a list of tables, a value was provided as null or empty string.", "tableNames" );
          dataAdapter.TableMappings.Add(tableName, tableNames[index]);
          tableName += (index + 1).ToString();
         }
        }
                   
        // 填充数据集使用默认表名称
        dataAdapter.Fill(dataSet);

        // 清除参数,以便再次使用.
        command.Parameters.Clear();
       }

       if( mustCloseConnection )
        connection.Close();
      }
      #endregion
           
      #region UpdateDataset 更新数据集
      /// <summary>
      /// 执行数据集更新到数据库,指定inserted, updated, or deleted命令.
      /// </summary>
      /// <remarks>
      /// 示例: 
      ///  UpdateDataset(conn, insertCommand, deleteCommand, updateCommand, dataSet, "Order");
      /// </remarks>
      /// <param name="insertCommand">[追加记录]一个有效的T-SQL语句或存储过程</param>
      /// <param name="deleteCommand">[删除记录]一个有效的T-SQL语句或存储过程</param>
      /// <param name="updateCommand">[更新记录]一个有效的T-SQL语句或存储过程</param>
      /// <param name="dataSet">要更新到数据库的DataSet</param>
      /// <param name="tableName">要更新到数据库的DataTable</param>
      public static void UpdateDataset(SqlCommand insertCommand, SqlCommand deleteCommand, SqlCommand updateCommand, DataSet dataSet, string tableName)
      {
       if( insertCommand == null ) throw new ArgumentNullException( "insertCommand" );
       if( deleteCommand == null ) throw new ArgumentNullException( "deleteCommand" );
       if( updateCommand == null ) throw new ArgumentNullException( "updateCommand" );
       if( tableName == null || tableName.Length == 0 ) throw new ArgumentNullException( "tableName" );

       // 创建SqlDataAdapter,当操作完成后释放.
       using (SqlDataAdapter dataAdapter = new SqlDataAdapter())
       {
        // 设置数据适配器命令
        dataAdapter.UpdateCommand = updateCommand;
        dataAdapter.InsertCommand = insertCommand;
        dataAdapter.DeleteCommand = deleteCommand;

        // 更新数据集改变到数据库
        dataAdapter.Update (dataSet, tableName);

        // 提交所有改变到数据集.
        dataSet.AcceptChanges();
       }
      }
      #endregion

      #region CreateCommand 创建一条SqlCommand命令
      /// <summary>
      /// 创建SqlCommand命令,指定数据库连接对象,存储过程名和参数.
      /// </summary>
      /// <remarks>
      /// 示例: 
      ///  SqlCommand command = CreateCommand(conn, "AddCustomer", "CustomerID", "CustomerName");
      /// </remarks>
      /// <param name="connection">一个有效的数据库连接对象</param>
      /// <param name="spName">存储过程名称</param>
      /// <param name="sourceColumns">源表的列名称数组</param>
      /// <returns>返回SqlCommand命令</returns>
      public static SqlCommand CreateCommand(SqlConnection connection, string spName, params string[] sourceColumns)
      {
       if( connection == null ) throw new ArgumentNullException( "connection" );
       if( spName == null || spName.Length == 0 ) throw new ArgumentNullException( "spName" );

       // 创建命令
       SqlCommand cmd = new SqlCommand( spName, connection );
       cmd.CommandType = CommandType.StoredProcedure;

       // 如果有参数值
       if ((sourceColumns != null) && (sourceColumns.Length > 0))
       {
        // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
        SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(connection, spName);

        // 将源表的列到映射到DataSet命令中.
        for (int index=0; index < sourceColumns.Length; index++)
         commandParameters[index].SourceColumn = sourceColumns[index];

        // Attach the discovered parameters to the SqlCommand object
        AttachParameters (cmd, commandParameters);
       }

       return cmd;
      }
      #endregion

      #region ExecuteNonQueryTypedParams 类型化参数(DataRow)
      /// <summary>
      /// 执行指定连接数据库连接字符串的存储过程,使用DataRow做为参数值,返回受影响的行数.
      /// </summary>
      /// <param name="connectionString">一个有效的数据库连接字符串</param>
      /// <param name="spName">存储过程名称</param>
      /// <param name="dataRow">使用DataRow作为参数值</param>
      /// <returns>返回影响的行数</returns>
      public static int ExecuteNonQueryTypedParams(String connectionString, String spName, DataRow dataRow)
      {
       if( connectionString == null || connectionString.Length == 0 ) throw new ArgumentNullException( "connectionString" );
       if( spName == null || spName.Length == 0 ) throw new ArgumentNullException( "spName" );
               
       // 如果row有值,存储过程必须初始化.
       if (dataRow != null && dataRow.ItemArray.Length > 0)
       {
        // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
        SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(connectionString, spName);
                   
        // 分配参数值
        AssignParameterValues(commandParameters, dataRow);
                                   
        return SqlHelper.ExecuteNonQuery(connectionString, CommandType.StoredProcedure, spName, commandParameters);
       }
       else
       {
        return SqlHelper.ExecuteNonQuery(connectionString, CommandType.StoredProcedure, spName);
       }
      }

      /// <summary>
      /// 执行指定连接数据库连接对象的存储过程,使用DataRow做为参数值,返回受影响的行数.
      /// </summary>
      /// <param name="connection">一个有效的数据库连接对象</param>
      /// <param name="spName">存储过程名称</param>
      /// <param name="dataRow">使用DataRow作为参数值</param>
      /// <returns>返回影响的行数</returns>
      public static int ExecuteNonQueryTypedParams(SqlConnection connection, String spName, DataRow dataRow)
      {
       if( connection == null ) throw new ArgumentNullException( "connection" );
       if( spName == null || spName.Length == 0 ) throw new ArgumentNullException( "spName" );

       // 如果row有值,存储过程必须初始化.
       if (dataRow != null && dataRow.ItemArray.Length > 0)
       {
        // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
        SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(connection, spName);
                   
        // 分配参数值
        AssignParameterValues(commandParameters, dataRow);
                                   
        return SqlHelper.ExecuteNonQuery(connection, CommandType.StoredProcedure, spName, commandParameters);
       }
       else
       {
        return SqlHelper.ExecuteNonQuery(connection, CommandType.StoredProcedure, spName);
       }
      }

      /// <summary>
      /// 执行指定连接数据库事物的存储过程,使用DataRow做为参数值,返回受影响的行数.
      /// </summary>
      /// <param name="transaction">一个有效的连接事务 object</param>
      /// <param name="spName">存储过程名称</param>
      /// <param name="dataRow">使用DataRow作为参数值</param>
      /// <returns>返回影响的行数</returns>
      public static int ExecuteNonQueryTypedParams(SqlTransaction transaction, String spName, DataRow dataRow)
      {
       if( transaction == null ) throw new ArgumentNullException( "transaction" );
       if( transaction != null && transaction.Connection == null ) throw new ArgumentException( "The transaction was rollbacked or commited, please provide an open transaction.", "transaction" );
       if( spName == null || spName.Length == 0 ) throw new ArgumentNullException( "spName" );

       // Sf the row has values, the store procedure parameters must be initialized
       if (dataRow != null && dataRow.ItemArray.Length > 0)
       {
        // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
        SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(transaction.Connection, spName);
                   
        // 分配参数值
        AssignParameterValues(commandParameters, dataRow);
                                   
        return SqlHelper.ExecuteNonQuery(transaction, CommandType.StoredProcedure, spName, commandParameters);
       }
       else
       {
        return SqlHelper.ExecuteNonQuery(transaction, CommandType.StoredProcedure, spName);
       }
      }
      #endregion

      #region ExecuteDatasetTypedParams 类型化参数(DataRow)
      /// <summary>
      /// 执行指定连接数据库连接字符串的存储过程,使用DataRow做为参数值,返回DataSet.
      /// </summary>
      /// <param name="connectionString">一个有效的数据库连接字符串</param>
      /// <param name="spName">存储过程名称</param>
      /// <param name="dataRow">使用DataRow作为参数值</param>
      /// <returns>返回一个包含结果集的DataSet.</returns>
      public static DataSet ExecuteDatasetTypedParams(string connectionString, String spName, DataRow dataRow)
      {
       if( connectionString == null || connectionString.Length == 0 ) throw new ArgumentNullException( "connectionString" );
       if( spName == null || spName.Length == 0 ) throw new ArgumentNullException( "spName" );

       //如果row有值,存储过程必须初始化.
       if ( dataRow != null && dataRow.ItemArray.Length > 0)
       {
        // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
        SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(connectionString, spName);
                   
        // 分配参数值
        AssignParameterValues(commandParameters, dataRow);
                   
        return SqlHelper.ExecuteDataset(connectionString, CommandType.StoredProcedure, spName, commandParameters);
       }
       else
       {
        return SqlHelper.ExecuteDataset(connectionString, CommandType.StoredProcedure, spName);
       }
      }

      /// <summary>
      /// 执行指定连接数据库连接对象的存储过程,使用DataRow做为参数值,返回DataSet.
      /// </summary>
      /// <param name="connection">一个有效的数据库连接对象</param>
      /// <param name="spName">存储过程名称</param>
      /// <param name="dataRow">使用DataRow作为参数值</param>
      /// <returns>返回一个包含结果集的DataSet.</returns>
      ///
      public static DataSet ExecuteDatasetTypedParams(SqlConnection connection, String spName, DataRow dataRow)
      {
       if( connection == null ) throw new ArgumentNullException( "connection" );
       if( spName == null || spName.Length == 0 ) throw new ArgumentNullException( "spName" );

       // 如果row有值,存储过程必须初始化.
       if( dataRow != null && dataRow.ItemArray.Length > 0)
       {
        // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
        SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(connection, spName);
                   
        // 分配参数值
        AssignParameterValues(commandParameters, dataRow);
                   
        return SqlHelper.ExecuteDataset(connection, CommandType.StoredProcedure, spName, commandParameters);
       }
       else
       {
        return SqlHelper.ExecuteDataset(connection, CommandType.StoredProcedure, spName);
       }
      }

      /// <summary>
      /// 执行指定连接数据库事务的存储过程,使用DataRow做为参数值,返回DataSet.
      /// </summary>
      /// <param name="transaction">一个有效的连接事务 object</param>
      /// <param name="spName">存储过程名称</param>
      /// <param name="dataRow">使用DataRow作为参数值</param>
      /// <returns>返回一个包含结果集的DataSet.</returns>
      public static DataSet ExecuteDatasetTypedParams(SqlTransaction transaction, String spName, DataRow dataRow)
      {
       if( transaction == null ) throw new ArgumentNullException( "transaction" );
       if( transaction != null && transaction.Connection == null ) throw new ArgumentException( "The transaction was rollbacked or commited, please provide an open transaction.", "transaction" );
       if( spName == null || spName.Length == 0 ) throw new ArgumentNullException( "spName" );

       // 如果row有值,存储过程必须初始化.
       if( dataRow != null && dataRow.ItemArray.Length > 0)
       {
        // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
        SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(transaction.Connection, spName);
                   
        // 分配参数值
        AssignParameterValues(commandParameters, dataRow);
                   
        return SqlHelper.ExecuteDataset(transaction, CommandType.StoredProcedure, spName, commandParameters);
       }
       else
       {
        return SqlHelper.ExecuteDataset(transaction, CommandType.StoredProcedure, spName);
       }
      }

      #endregion

      #region ExecuteReaderTypedParams 类型化参数(DataRow)
      /// <summary>
      /// 执行指定连接数据库连接字符串的存储过程,使用DataRow做为参数值,返回DataReader.
      /// </summary>
      /// <param name="connectionString">一个有效的数据库连接字符串</param>
      /// <param name="spName">存储过程名称</param>
      /// <param name="dataRow">使用DataRow作为参数值</param>
      /// <returns>返回包含结果集的SqlDataReader</returns>
      public static SqlDataReader ExecuteReaderTypedParams(String connectionString, String spName, DataRow dataRow)
      {
       if( connectionString == null || connectionString.Length == 0 ) throw new ArgumentNullException( "connectionString" );
       if( spName == null || spName.Length == 0 ) throw new ArgumentNullException( "spName" );
               
       // 如果row有值,存储过程必须初始化.
       if ( dataRow != null && dataRow.ItemArray.Length > 0 )
       {
        // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
        SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(connectionString, spName);
                   
        // 分配参数值
        AssignParameterValues(commandParameters, dataRow);
                   
        return SqlHelper.ExecuteReader(connectionString, CommandType.StoredProcedure, spName, commandParameters);
       }
       else
       {
        return SqlHelper.ExecuteReader(connectionString, CommandType.StoredProcedure, spName);
       }
      }

                   
      /// <summary>
      /// 执行指定连接数据库连接对象的存储过程,使用DataRow做为参数值,返回DataReader.
      /// </summary>
      /// <param name="connection">一个有效的数据库连接对象</param>
      /// <param name="spName">存储过程名称</param>
      /// <param name="dataRow">使用DataRow作为参数值</param>
      /// <returns>返回包含结果集的SqlDataReader</returns>
      public static SqlDataReader ExecuteReaderTypedParams(SqlConnection connection, String spName, DataRow dataRow)
      {
       if( connection == null ) throw new ArgumentNullException( "connection" );
       if( spName == null || spName.Length == 0 ) throw new ArgumentNullException( "spName" );

       // 如果row有值,存储过程必须初始化.
       if( dataRow != null && dataRow.ItemArray.Length > 0)
       {
        // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
        SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(connection, spName);
                   
        // 分配参数值
        AssignParameterValues(commandParameters, dataRow);
                   
        return SqlHelper.ExecuteReader(connection, CommandType.StoredProcedure, spName, commandParameters);
       }
       else
       {
        return SqlHelper.ExecuteReader(connection, CommandType.StoredProcedure, spName);
       }
      }
           
      /// <summary>
      /// 执行指定连接数据库事物的存储过程,使用DataRow做为参数值,返回DataReader.
      /// </summary>
      /// <param name="transaction">一个有效的连接事务 object</param>
      /// <param name="spName">存储过程名称</param>
      /// <param name="dataRow">使用DataRow作为参数值</param>
      /// <returns>返回包含结果集的SqlDataReader</returns>
      public static SqlDataReader ExecuteReaderTypedParams(SqlTransaction transaction, String spName, DataRow dataRow)
      {
       if( transaction == null ) throw new ArgumentNullException( "transaction" );
       if( transaction != null && transaction.Connection == null ) throw new ArgumentException( "The transaction was rollbacked or commited, please provide an open transaction.", "transaction" );
       if( spName == null || spName.Length == 0 ) throw new ArgumentNullException( "spName" );

       // 如果row有值,存储过程必须初始化.
       if( dataRow != null && dataRow.ItemArray.Length > 0 )
       {
        // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
        SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(transaction.Connection, spName);
                   
        // 分配参数值
        AssignParameterValues(commandParameters, dataRow);
                   
        return SqlHelper.ExecuteReader(transaction, CommandType.StoredProcedure, spName, commandParameters);
       }
       else
       {
        return SqlHelper.ExecuteReader(transaction, CommandType.StoredProcedure, spName);
       }
      }
      #endregion

      #region ExecuteScalarTypedParams 类型化参数(DataRow)
      /// <summary>
      /// 执行指定连接数据库连接字符串的存储过程,使用DataRow做为参数值,返回结果集中的第一行第一列.
      /// </summary>
      /// <param name="connectionString">一个有效的数据库连接字符串</param>
      /// <param name="spName">存储过程名称</param>
      /// <param name="dataRow">使用DataRow作为参数值</param>
      /// <returns>返回结果集中的第一行第一列</returns>
      public static object ExecuteScalarTypedParams(String connectionString, String spName, DataRow dataRow)
      {
       if( connectionString == null || connectionString.Length == 0 ) throw new ArgumentNullException( "connectionString" );
       if( spName == null || spName.Length == 0 ) throw new ArgumentNullException( "spName" );
               
       // 如果row有值,存储过程必须初始化.
       if( dataRow != null && dataRow.ItemArray.Length > 0)
       {
        // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
        SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(connectionString, spName);
                   
        // 分配参数值
        AssignParameterValues(commandParameters, dataRow);
                   
        return SqlHelper.ExecuteScalar(connectionString, CommandType.StoredProcedure, spName, commandParameters);
       }
       else
       {
        return SqlHelper.ExecuteScalar(connectionString, CommandType.StoredProcedure, spName);
       }
      }

      /// <summary>
      /// 执行指定连接数据库连接对象的存储过程,使用DataRow做为参数值,返回结果集中的第一行第一列.
      /// </summary>
      /// <param name="connection">一个有效的数据库连接对象</param>
      /// <param name="spName">存储过程名称</param>
      /// <param name="dataRow">使用DataRow作为参数值</param>
      /// <returns>返回结果集中的第一行第一列</returns>
      public static object ExecuteScalarTypedParams(SqlConnection connection, String spName, DataRow dataRow)
      {
       if( connection == null ) throw new ArgumentNullException( "connection" );
       if( spName == null || spName.Length == 0 ) throw new ArgumentNullException( "spName" );

       // 如果row有值,存储过程必须初始化.
       if( dataRow != null && dataRow.ItemArray.Length > 0)
       {
        // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
        SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(connection, spName);
                   
        // 分配参数值
        AssignParameterValues(commandParameters, dataRow);
                   
        return SqlHelper.ExecuteScalar(connection, CommandType.StoredProcedure, spName, commandParameters);
       }
       else
       {
        return SqlHelper.ExecuteScalar(connection, CommandType.StoredProcedure, spName);
       }
      }

      /// <summary>
      /// 执行指定连接数据库事务的存储过程,使用DataRow做为参数值,返回结果集中的第一行第一列.
      /// </summary>
      /// <param name="transaction">一个有效的连接事务 object</param>
      /// <param name="spName">存储过程名称</param>
      /// <param name="dataRow">使用DataRow作为参数值</param>
      /// <returns>返回结果集中的第一行第一列</returns>
      public static object ExecuteScalarTypedParams(SqlTransaction transaction, String spName, DataRow dataRow)
      {
       if( transaction == null ) throw new ArgumentNullException( "transaction" );
       if( transaction != null && transaction.Connection == null ) throw new ArgumentException( "The transaction was rollbacked or commited, please provide an open transaction.", "transaction" );
       if( spName == null || spName.Length == 0 ) throw new ArgumentNullException( "spName" );

       // 如果row有值,存储过程必须初始化.
       if( dataRow != null && dataRow.ItemArray.Length > 0)
       {
        // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
        SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(transaction.Connection, spName);
                   
        // 分配参数值
        AssignParameterValues(commandParameters, dataRow);
                   
        return SqlHelper.ExecuteScalar(transaction, CommandType.StoredProcedure, spName, commandParameters);
       }
       else
       {
        return SqlHelper.ExecuteScalar(transaction, CommandType.StoredProcedure, spName);
       }
      }
      #endregion

      #region ExecuteXmlReaderTypedParams 类型化参数(DataRow)
      /// <summary>
      /// 执行指定连接数据库连接对象的存储过程,使用DataRow做为参数值,返回XmlReader类型的结果集.
      /// </summary>
      /// <param name="connection">一个有效的数据库连接对象</param>
      /// <param name="spName">存储过程名称</param>
      /// <param name="dataRow">使用DataRow作为参数值</param>
      /// <returns>返回XmlReader结果集对象.</returns>
      public static XmlReader ExecuteXmlReaderTypedParams(SqlConnection connection, String spName, DataRow dataRow)
      {
       if( connection == null ) throw new ArgumentNullException( "connection" );
       if( spName == null || spName.Length == 0 ) throw new ArgumentNullException( "spName" );

       // 如果row有值,存储过程必须初始化.
       if( dataRow != null && dataRow.ItemArray.Length > 0)
       {
        // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
        SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(connection, spName);
                   
        // 分配参数值
        AssignParameterValues(commandParameters, dataRow);
                   
        return SqlHelper.ExecuteXmlReader(connection, CommandType.StoredProcedure, spName, commandParameters);
       }
       else
       {
        return SqlHelper.ExecuteXmlReader(connection, CommandType.StoredProcedure, spName);
       }
      }

      /// <summary>
      /// 执行指定连接数据库事务的存储过程,使用DataRow做为参数值,返回XmlReader类型的结果集.
      /// </summary>
      /// <param name="transaction">一个有效的连接事务 object</param>
      /// <param name="spName">存储过程名称</param>
      /// <param name="dataRow">使用DataRow作为参数值</param>
      /// <returns>返回XmlReader结果集对象.</returns>
      public static XmlReader ExecuteXmlReaderTypedParams(SqlTransaction transaction, String spName, DataRow dataRow)
      {
       if( transaction == null ) throw new ArgumentNullException( "transaction" );
       if( transaction != null && transaction.Connection == null ) throw new ArgumentException( "The transaction was rollbacked or commited, please provide an open transaction.", "transaction" );
       if( spName == null || spName.Length == 0 ) throw new ArgumentNullException( "spName" );

       // 如果row有值,存储过程必须初始化.
       if( dataRow != null && dataRow.ItemArray.Length > 0)
       {
        // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
        SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(transaction.Connection, spName);
                   
        // 分配参数值
        AssignParameterValues(commandParameters, dataRow);
                   
        return SqlHelper.ExecuteXmlReader(transaction, CommandType.StoredProcedure, spName, commandParameters);
       }
       else
       {
        return SqlHelper.ExecuteXmlReader(transaction, CommandType.StoredProcedure, spName);
       }
      }
      #endregion

     }

     /// <summary>
     /// SqlHelperParameterCache提供缓存存储过程参数,并能够在运行时从存储过程中探索参数.
     /// </summary>
     public sealed class SqlHelperParameterCache
     {
      #region 私有方法,字段,构造函数
      // 私有构造函数,妨止类被实例化.
      private SqlHelperParameterCache() {}

      // 这个方法要注意
      private static Hashtable paramCache = Hashtable.Synchronized(new Hashtable());

      /// <summary>
      /// 探索运行时的存储过程,返回SqlParameter参数数组.
      /// 初始化参数值为 DBNull.Value.
      /// </summary>
      /// <param name="connection">一个有效的数据库连接</param>
      /// <param name="spName">存储过程名称</param>
      /// <param name="includeReturnValueParameter">是否包含返回值参数</param>
      /// <returns>返回SqlParameter参数数组</returns>
      private static SqlParameter[] DiscoverSpParameterSet(SqlConnection connection, string spName, bool includeReturnValueParameter)
      {
       if( connection == null ) throw new ArgumentNullException( "connection" );
       if( spName == null || spName.Length == 0 ) throw new ArgumentNullException( "spName" );

       SqlCommand cmd = new SqlCommand(spName, connection);
       cmd.CommandType = CommandType.StoredProcedure;

       connection.Open();
       // 检索cmd指定的存储过程的参数信息,并填充到cmd的Parameters参数集中.
       SqlCommandBuilder.DeriveParameters(cmd);
       connection.Close();
       // 如果不包含返回值参数,将参数集中的每一个参数删除.
       if (!includeReturnValueParameter)
       {
        cmd.Parameters.RemoveAt(0);
       }
                   
       // 创建参数数组
       SqlParameter[] discoveredParameters = new SqlParameter[cmd.Parameters.Count];
       // 将cmd的Parameters参数集复制到discoveredParameters数组.
       cmd.Parameters.CopyTo(discoveredParameters, 0);

       // 初始化参数值为 DBNull.Value.
       foreach (SqlParameter discoveredParameter in discoveredParameters)
       {
        discoveredParameter.Value = DBNull.Value;
       }
       return discoveredParameters;
      }

      /// <summary>
      /// SqlParameter参数数组的深层拷贝.
      /// </summary>
      /// <param name="originalParameters">原始参数数组</param>
      /// <returns>返回一个同样的参数数组</returns>
      private static SqlParameter[] CloneParameters(SqlParameter[] originalParameters)
      {
       SqlParameter[] clonedParameters = new SqlParameter[originalParameters.Length];

       for (int i = 0, j = originalParameters.Length; i < j; i++)
       {
        clonedParameters[i] = (SqlParameter)((ICloneable)originalParameters[i]).Clone();
       }

       return clonedParameters;
      }

      #endregion 私有方法,字段,构造函数结束

      #region 缓存方法

      /// <summary>
      /// 追加参数数组到缓存.
      /// </summary>
      /// <param name="connectionString">一个有效的数据库连接字符串</param>
      /// <param name="commandText">存储过程名或SQL语句</param>
      /// <param name="commandParameters">要缓存的参数数组</param>
      public static void CacheParameterSet(string connectionString, string commandText, params SqlParameter[] commandParameters)
      {
       if( connectionString == null || connectionString.Length == 0 ) throw new ArgumentNullException( "connectionString" );
       if( commandText == null || commandText.Length == 0 ) throw new ArgumentNullException( "commandText" );

       string hashKey = connectionString + ":" + commandText;

       paramCache[hashKey] = commandParameters;
      }

      /// <summary>
      /// 从缓存中获取参数数组.
      /// </summary>
      /// <param name="connectionString">一个有效的数据库连接字符</param>
      /// <param name="commandText">存储过程名或SQL语句</param>
      /// <returns>参数数组</returns>
      public static SqlParameter[] GetCachedParameterSet(string connectionString, string commandText)
      {
       if( connectionString == null || connectionString.Length == 0 ) throw new ArgumentNullException( "connectionString" );
       if( commandText == null || commandText.Length == 0 ) throw new ArgumentNullException( "commandText" );

       string hashKey = connectionString + ":" + commandText;

       SqlParameter[] cachedParameters = paramCache[hashKey] as SqlParameter[];
       if (cachedParameters == null)
       {           
        return null;
       }
       else
       {
        return CloneParameters(cachedParameters);
       }
      }

      #endregion 缓存方法结束

      #region 检索指定的存储过程的参数集

      /// <summary>
      /// 返回指定的存储过程的参数集
      /// </summary>
      /// <remarks>
      /// 这个方法将查询数据库,并将信息存储到缓存.
      /// </remarks>
      /// <param name="connectionString">一个有效的数据库连接字符</param>
      /// <param name="spName">存储过程名</param>
      /// <returns>返回SqlParameter参数数组</returns>
      public static SqlParameter[] GetSpParameterSet(string connectionString, string spName)
      {
       return GetSpParameterSet(connectionString, spName, false);
      }

      /// <summary>
      /// 返回指定的存储过程的参数集
      /// </summary>
      /// <remarks>
      /// 这个方法将查询数据库,并将信息存储到缓存.
      /// </remarks>
      /// <param name="connectionString">一个有效的数据库连接字符.</param>
      /// <param name="spName">存储过程名</param>
      /// <param name="includeReturnValueParameter">是否包含返回值参数</param>
      /// <returns>返回SqlParameter参数数组</returns>
      public static SqlParameter[] GetSpParameterSet(string connectionString, string spName, bool includeReturnValueParameter)
      {
       if( connectionString == null || connectionString.Length == 0 ) throw new ArgumentNullException( "connectionString" );
       if( spName == null || spName.Length == 0 ) throw new ArgumentNullException( "spName" );

       using(SqlConnection connection = new SqlConnection(connectionString))
       {
        return GetSpParameterSetInternal(connection, spName, includeReturnValueParameter);
       }
      }

      /// <summary>
      /// [内部]返回指定的存储过程的参数集(使用连接对象).
      /// </summary>
      /// <remarks>
      /// 这个方法将查询数据库,并将信息存储到缓存.
      /// </remarks>
      /// <param name="connection">一个有效的数据库连接字符</param>
      /// <param name="spName">存储过程名</param>
      /// <returns>返回SqlParameter参数数组</returns>
      internal static SqlParameter[] GetSpParameterSet(SqlConnection connection, string spName)
      {
       return GetSpParameterSet(connection, spName, false);
      }

      /// <summary>
      /// [内部]返回指定的存储过程的参数集(使用连接对象)
      /// </summary>
      /// <remarks>
      /// 这个方法将查询数据库,并将信息存储到缓存.
      /// </remarks>
      /// <param name="connection">一个有效的数据库连接对象</param>
      /// <param name="spName">存储过程名</param>
      /// <param name="includeReturnValueParameter">
      /// 是否包含返回值参数
      /// </param>
      /// <returns>返回SqlParameter参数数组</returns>
      internal static SqlParameter[] GetSpParameterSet(SqlConnection connection, string spName, bool includeReturnValueParameter)
      {
       if( connection == null ) throw new ArgumentNullException( "connection" );
       using (SqlConnection clonedConnection = (SqlConnection)((ICloneable)connection).Clone())
       {
        return GetSpParameterSetInternal(clonedConnection, spName, includeReturnValueParameter);
       }
      }

      /// <summary>
      /// [私有]返回指定的存储过程的参数集(使用连接对象)
      /// </summary>
      /// <param name="connection">一个有效的数据库连接对象</param>
      /// <param name="spName">存储过程名</param>
      /// <param name="includeReturnValueParameter">是否包含返回值参数</param>
      /// <returns>返回SqlParameter参数数组</returns>
      private static SqlParameter[] GetSpParameterSetInternal(SqlConnection connection, string spName, bool includeReturnValueParameter)
      {
       if( connection == null ) throw new ArgumentNullException( "connection" );
       if( spName == null || spName.Length == 0 ) throw new ArgumentNullException( "spName" );

       string hashKey = connection.ConnectionString + ":" + spName + (includeReturnValueParameter ? ":include ReturnValue Parameter":"");

       SqlParameter[] cachedParameters;
               
       cachedParameters = paramCache[hashKey] as SqlParameter[];
       if (cachedParameters == null)
       {   
        SqlParameter[] spParameters = DiscoverSpParameterSet(connection, spName, includeReturnValueParameter);
        paramCache[hashKey] = spParameters;
        cachedParameters = spParameters;
       }
               
       return CloneParameters(cachedParameters);
      }
           
      #endregion 参数集检索结束

     }
    }

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  • 原文地址:https://www.cnblogs.com/huyong/p/2685620.html
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