Silverlight通过Webservice连接数据库操作 .

  silverlight（简称SL）进行数据库操作，有多种方法，这里介绍最传统的通过WebService（简称WS）实现方式。本文的主要目的是在SL不支持DataSet和DataTable的基础上，提供通用的返回数据的WS方法。

一：创建项目

    首先，创建SL应用程序，如QuestionsDbSL，创建的时候选择生成网站QuestionsDbSL.Web。另外，往往大家不想将SQL语句写在主应用程序中，所以，这里还需要创建一个业务层QuestionsDbSLServices。同时，实体层，我们创建为QuestionsDbSLModel。

    QuestionsDbSL：SL主应用程序；

    QuestionsDbSL.Web：承载SL主应用程序的网站，同时也提供WS；

    QuestionsDbSLServices：SL类库项目，提供逻辑层；
    QuestionsDbSLModel：SL类库项目，提供实体层，对应数据库表。

 

二：必要的辅助类和文件

    第一个辅助类，就是SqlHelper，对数据库的直接操作，由它提供直接对数据库的操作。见附件一：SqlHelper.cs。该文件创建在QuestionsDbSL.Web.ClientBin中。

    第二个是配置文件Web.config，这里需要用到的是定义数据连接字符串：

 <ppSettings>
  <add key="ConnString" value="server =192.168.0.96; user id = sa; password = sa; database = xxxProp"/>
 </appSettings>

三：WS函数

    首先是获取记录集的函数：

    public List<BaseVars> GetListBaseVars(string sql, params SqlParameter[] commandParams)

    很遗憾的一点是，SL不支持DataSet或者DataTable，所以你无法直接返回一个记录集。但你可以通过返回一个List的方法来迂回解决。

    如数据库表Student，则你可以返回一个List<Student>。问题的关键是，这样一来，你不得不为每一类查询提供一个WS函数。也许你会尝试用List<T>来解决这个问题，同样遗憾的是，SL调用WS函数的时候，只能序列化一般类型的类，所以我们必须换一个方式解决该问题。

    要知道，数据表也就是各种基础类型的字段所组成的，所以，我们来模拟一张表就是：

  /// <summary>
    /// 模拟数据库表
    /// PS：一张表的字段不外乎几个基本数据类型，查询出来的值，在这里进行赋值
    /// 本类的一个实例，相当于是一条记录，本类的一个实例数组，就相当于是datatable
    /// 在UI端，你可将本类的实例数组转换为数据源
    /// </summary>
    public class BaseVars
    {
        public BaseVars()
        {
            ListString = new List<string>();
            ListInt = new List<int>();
            ListBool = new List<bool>();
            ListByte = new List<byte>();
            ListFloat = new List<float>();
            ListDouble = new List<double>();
        }
        public List<string> ListString { get; set; }
        public List<int> ListInt { get; set; }
        public List<bool> ListBool { get; set; }
        public List<byte> ListByte { get; set; }
        public List<float> ListFloat { get; set; }
        public List<double> ListDouble { get; set; }
    }
    则，WS函数就是如下：
        /// <summary>
        /// 通用查询方法
        /// 1：查询返回的记录，将会生成实例BaseVars；
        /// 2：本方法返回BaseVars的列表；
        /// 3：在调用方，要重新对数据进行组织，以便进行展示；
        /// </summary>
        /// <param name="sql"></param>
        /// <param name="commandParams"></param>
        /// <returns></returns>
        [WebMethod]
        public List<BaseVars> GetListBaseVars(string sql, params SqlParameter[] commandParams)
        {
            List<BaseVars> lr = new List<BaseVars>();
            using (DataSet ds = SqlHelper.ExecuteDataSet(sql, commandParams))
            {
                if (ds == null || ds.Tables[0].Rows.Count < 0)
                {
                    return null;
                }
                lr = ListBaseDataSet.DataSetToListBaseVars(ds, 0);
            }
            return lr;
        }

 注意到上段代码中，ListBaseDataSet.DataSetToListBaseVars(ds, 0)就是将一个DataSet转换为BaseVars的一个实例列表。ListBaseDataSet.cs见附件二。

 

四：WS调用方

    WS的调用在SL都是异步调用，WS提供的函数名在调用方都会被自动加上一个后缀Async。所以，如果你觉得有必要，你就需要提供一个委托函数来在WS调用完毕的做点什么，如下：

wss.GetListBaseVarsCompleted += new EventHandler<QuestionsDbSLServices.ServiceReferenceYi.GetListBaseVarsCompletedEventArgs>(wss_GetListBaseVarsCompleted);

  wss是WS的实例，wss_GetListBaseVarsCompleted就是该委托函数。在该委托函数中，我是将得到的数据记录重构成一个具体对象的列表。

    void wss_GetListBaseVarsCompleted(object sender, QuestionsDbSLServices.ServiceReferenceYi.GetListBaseVarsCompletedEventArgs e)
        {
            ServiceReferenceYi.BaseVars[] lr = e.Result;
            foreach (var item in lr)
            {
                QuestionsDbSLModel.Res_Source ds = new QuestionsDbSLModel.Res_Source();
                ds.SourceId = item.ListInt[0];
                ds.SourceName = item.ListString[0];
                ds.DispOrder = item.ListInt[1];
                ldResource.Add(ds);
            }
        }

五：一个BUG

     在业务层QuestionsDbSLServices引用WS后，在QuestionsDbSL使用QuestionsDbSLServices后会报错，查询结果是配置文件ServiceReferences.ClientConfig未被包含在XAP中。如果你直接在WEB中调用WS，则在打包项目的时候，ServiceReferences.ClientConfig被自动打包进去。

    解决的办法是，你在WEB中，需要手动创建一个ServiceReferences.ClientConfig，然后将QuestionsDbSLServices的该文件的内容COPY进去。

SqlHelper.cs实例如下：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Data.SqlClient;
using System.Configuration;
using System.Data;
using System.Xml;
using System.Diagnostics;

namespace QuestionsDbSL.Web.ClientBin
{
    [DebuggerStepThrough]
    public sealed class SqlHelper
    {
        #region private utility methods & constructors

        //Since this class provides only static methods, make the default constructor private to prevent 
        //instances from being created with "new SqlHelper()".
        private SqlHelper() { }

        /// <summary>
        /// This method is used to attach array of SqlParameters to a SqlCommand.
        /// This method will assign a value of DbNull to any parameter with a direction of
        /// InputOutput and a value of null.
        /// This behavior will prevent default values from being used, but
        /// this will be the less common case than an intended pure output parameter (derived as InputOutput)
        /// where the user provided no input value.
        /// </summary>
        /// <param name="command">The command to which the parameters will be added</param>
        /// <param name="commandParameters">an array of SqlParameters tho be added to command</param>
        private static void AttachParameters(SqlCommand command, SqlParameter[] commandParameters)
        {
            foreach (SqlParameter p in commandParameters)
            {
                //check for derived output value with no value assigned
                if ((p.Direction == ParameterDirection.InputOutput) && (p.Value == null))
                {
                    p.Value = DBNull.Value;
                }
                command.Parameters.Add(p);
            }
        }

        /// <summary>
        /// This method assigns an array of values to an array of SqlParameters.
        /// </summary>
        /// <param name="commandParameters">array of SqlParameters to be assigned values</param>
        /// <param name="parameterValues">array of Components holding the values to be assigned</param>
        private static void AssignParameterValues(SqlParameter[] commandParameters, object[] parameterValues)
        {
            if ((commandParameters == null) || (parameterValues == null))
            {
                //do nothing if we get no data
                return;
            }

            // we must have the same number of values as we pave parameters to put them in
            if (commandParameters.Length != parameterValues.Length)
            {
                throw new ArgumentException("Parameter count does not match Parameter Value count.");
            }

            //iterate through the SqlParameters, assigning the values from the corresponding position in the 
            //value array
            for (int i = 0, j = commandParameters.Length; i < j; i++)
            {
                commandParameters[i].Value = parameterValues[i];
            }
        }

        /// <summary>
        /// This method opens (if necessary) and assigns a connection, transaction, command type and parameters 
        /// to the provided command.
        /// </summary>
        /// <param name="command">the SqlCommand to be prepared</param>
        /// <param name="connection">a valid SqlConnection, on which to execute this command</param>
        /// <param name="transaction">a valid SqlTransaction, or 'null'</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <param name="commandParameters">an array of SqlParameters to be associated with the command or 'null' if no parameters are required</param>
        private static void PrepareCommand(SqlCommand command, SqlConnection connection, SqlTransaction transaction, CommandType commandType, string commandText, SqlParameter[] commandParameters)
        {
            //if the provided connection is not open, we will open it
            if (connection.State != ConnectionState.Open)
                connection.Open();

            //associate the connection with the command
            command.Connection = connection;
            command.CommandTimeout = 180;

            //set the command text (stored procedure name or SQL statement)
            command.CommandText = commandText;

            //if we were provided a transaction, assign it.
            if (transaction != null)
                command.Transaction = transaction;

            //set the command type
            command.CommandType = commandType;

            //attach the command parameters if they are provided
            if (commandParameters != null)
                AttachParameters(command, commandParameters);

            return;
        }


        #endregion private utility methods & constructors

        #region DataHelpers

        public static string CheckNull(object obj)
        {
            return (string)obj;
        }

        public static string CheckNull(DBNull obj)
        {
            return null;
        }

        #endregion

        #region AddParameters

        public static object CheckForNullString(string text)
        {
            if (text == null || text.Trim().Length == 0)
            {
                return DBNull.Value;
            }
            else
            {
                return text;
            }
        }

        public static SqlParameter MakeInParam(string ParamName, object Value)
        {
            return new SqlParameter(ParamName, Value);
        }

        /// <summary>
        /// Make input param.
        /// </summary>
        /// <param name="ParamName">Name of param.</param>
        /// <param name="DbType">Param type.</param>
        /// <param name="Size">Param size.</param>
        /// <param name="Value">Param value.</param>
        /// <returns>New parameter.</returns>
        public static SqlParameter MakeInParam(string ParamName, SqlDbType DbType, int Size, object Value)
        {
            return MakeParam(ParamName, DbType, Size, ParameterDirection.Input, Value);
        }

        /// <summary>
        /// Make input param.
        /// </summary>
        /// <param name="ParamName">Name of param.</param>
        /// <param name="DbType">Param type.</param>
        /// <param name="Size">Param size.</param>
        /// <returns>New parameter.</returns>
        public static SqlParameter MakeOutParam(string ParamName, SqlDbType DbType, int Size)
        {
            return MakeParam(ParamName, DbType, Size, ParameterDirection.Output, null);
        }

        /// <summary>
        /// Make stored procedure param.
        /// </summary>
        /// <param name="ParamName">Name of param.</param>
        /// <param name="DbType">Param type.</param>
        /// <param name="Size">Param size.</param>
        /// <param name="Direction">Parm direction.</param>
        /// <param name="Value">Param value.</param>
        /// <returns>New parameter.</returns>
        public static SqlParameter MakeParam(string ParamName, SqlDbType DbType, Int32 Size, ParameterDirection Direction, object Value)
        {
            SqlParameter param;

            if (Size > 0)
                param = new SqlParameter(ParamName, DbType, Size);
            else
                param = new SqlParameter(ParamName, DbType);

            param.Direction = Direction;
            if (!(Direction == ParameterDirection.Output && Value == null))
                param.Value = Value;

            return param;
        }


        #endregion

        #region ExecuteNonQuery

        /// <summary>
        /// 执行一个简单的Sqlcommand 没有返回结果
        /// </summary>
        ///  例如:  
        ///  int result = ExecuteNonQuery("delete from test where 1>2 ");  返回 result =0
        /// <param name="commandText">只能是sql语句</param>
        /// <returns>受影响的行数</returns>
        public static int ExecuteNonQuery(string commandText)
        {
            return ExecuteNonQuery(ConfigurationManager.AppSettings["ConnString"], CommandType.Text, commandText, (SqlParameter[])null);
        }

        /// <summary>
        /// 执行一个简单的Sqlcommand 没有返回结果
        /// </summary>
        /// 例如:    
        ///  int result = ExecuteNonQuery("delete from test where  tt =@tt", new SqlParameter("@tt", 24));
        /// <param name="commandText">只能是sql语句</param>
        /// <param name="commandParameters">参数</param>
        /// <returns>受影响的行数</returns>
        public static int ExecuteNonQuery(string commandText, params SqlParameter[] commandParameters)
        {
            int i = 0;
            using (SqlConnection cn = new SqlConnection(ConfigurationManager.AppSettings["ConnString"]))
            {
                cn.Open();
                return ExecuteNonQuery(cn, CommandType.Text, commandText, commandParameters);
            }
        }

        /// <summary>
        /// Execute a SqlCommand (that returns no resultset and takes no parameters) against the database specified in 
        /// the connection string. 
        /// </summary>
        /// <remarks>
        /// e.g.:  
        ///  int result = ExecuteNonQuery(connString, CommandType.StoredProcedure, "PublishOrders");
        /// </remarks>
        /// <param name="connectionString">a valid connection string for a SqlConnection</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <returns>an int representing the number of rows affected by the command</returns>
        public static int ExecuteNonQuery(string connectionString, string commandText)
        {
            //pass through the call providing null for the set of SqlParameters
            return ExecuteNonQuery(connectionString, CommandType.Text, commandText, (SqlParameter[])null);
        }

        /// <summary>
        /// Execute a SqlCommand (that returns no resultset and takes no parameters) against the database specified in 
        /// the connection string. 
        /// </summary>
        /// <remarks>
        /// e.g.:  
        ///  int result = ExecuteNonQuery(connString, CommandType.StoredProcedure, "PublishOrders");
        /// </remarks>
        /// <param name="connectionString">a valid connection string for a SqlConnection</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <returns>an int representing the number of rows affected by the command</returns>
        public static int ExecuteNonQuery(string connectionString, CommandType commandType, string commandText)
        {
            //pass through the call providing null for the set of SqlParameters
            return ExecuteNonQuery(connectionString, commandType, commandText, (SqlParameter[])null);
        }

        /// <summary>
        /// Execute a SqlCommand (that returns no resultset) against the database specified in the connection string 
        /// using the provided parameters.
        /// </summary>
        /// <remarks>
        /// e.g.:  
        ///  int result = ExecuteNonQuery(connString, CommandType.StoredProcedure, "PublishOrders", new SqlParameter("@prodid", 24));
        /// </remarks>
        /// <param name="connectionString">a valid connection string for a SqlConnection</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <param name="commandParameters">an array of SqlParamters used to execute the command</param>
        /// <returns>an int representing the number of rows affected by the command</returns>
        public static int ExecuteNonQuery(string connectionString, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
        {
            //create & open a SqlConnection, and dispose of it after we are done.
            using (SqlConnection cn = new SqlConnection(connectionString))
            {
                cn.Open();

                //call the overload that takes a connection in place of the connection string
                return ExecuteNonQuery(cn, commandType, commandText, commandParameters);
            }
        }

        /// <summary>
        /// Execute a SqlCommand (that returns no resultset and takes no parameters) against the provided SqlConnection. 
        /// </summary>
        /// <remarks>
        /// e.g.:  
        ///  int result = ExecuteNonQuery(conn, CommandType.StoredProcedure, "PublishOrders");
        /// </remarks>
        /// <param name="connection">a valid SqlConnection</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <returns>an int representing the number of rows affected by the command</returns>
        public static int ExecuteNonQuery(SqlConnection connection, string commandText)
        {
            //pass through the call providing null for the set of SqlParameters
            return ExecuteNonQuery(connection, CommandType.Text, commandText, (SqlParameter[])null);
        }

        /// <summary>
        /// Execute a SqlCommand (that returns no resultset and takes no parameters) against the provided SqlConnection. 
        /// </summary>
        /// <remarks>
        /// e.g.:  
        ///  int result = ExecuteNonQuery(conn, CommandType.StoredProcedure, "PublishOrders");
        /// </remarks>
        /// <param name="connection">a valid SqlConnection</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <returns>an int representing the number of rows affected by the command</returns>
        public static int ExecuteNonQuery(SqlConnection connection, CommandType commandType, string commandText)
        {
            //pass through the call providing null for the set of SqlParameters
            return ExecuteNonQuery(connection, commandType, commandText, (SqlParameter[])null);
        }

        /// <summary>
        /// Execute a SqlCommand (that returns no resultset) against the specified SqlConnection 
        /// using the provided parameters.
        /// </summary>
        /// <remarks>
        /// e.g.:  
        ///  int result = ExecuteNonQuery(conn, CommandType.StoredProcedure, "PublishOrders", new SqlParameter("@prodid", 24));
        /// </remarks>
        /// <param name="connection">a valid SqlConnection</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <param name="commandParameters">an array of SqlParamters used to execute the command</param>
        /// <returns>an int representing the number of rows affected by the command</returns>
        public static int ExecuteNonQuery(SqlConnection connection, string commandText, params SqlParameter[] commandParameters)
        {
            return ExecuteNonQuery(connection, CommandType.Text, commandText, commandParameters);
        }

        /// <summary>
        /// Execute a SqlCommand (that returns no resultset) against the specified SqlConnection 
        /// using the provided parameters.
        /// </summary>
        /// <remarks>
        /// e.g.:  
        ///  int result = ExecuteNonQuery(conn, CommandType.StoredProcedure, "PublishOrders", new SqlParameter("@prodid", 24));
        /// </remarks>
        /// <param name="connection">a valid SqlConnection</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <param name="commandParameters">an array of SqlParamters used to execute the command</param>
        /// <returns>an int representing the number of rows affected by the command</returns>
        public static int ExecuteNonQuery(SqlConnection connection, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
        {
            //create a command and prepare it for execution
            SqlCommand cmd = new SqlCommand();
            PrepareCommand(cmd, connection, (SqlTransaction)null, commandType, commandText, commandParameters);

            //finally, execute the command.
            int retval = cmd.ExecuteNonQuery();

            // detach the SqlParameters from the command object, so they can be used again.
            cmd.Parameters.Clear();
            if (connection.State == ConnectionState.Open)
                connection.Close();
            return retval;
        }

        /// <summary>
        /// 执行一个简单的Sqlcommand 没有返回结果
        /// </summary>
        ///  例如:  
        ///  int result = ExecuteNonQuery(myTran,"delete from test where 1>2 ");  返回 result =0
        /// <param name="transaction">事务名称</param>
        /// <param name="commandText">只能是sql语句</param>
        /// <returns>受影响的行数</returns>
        public static int ExecuteNonQuery(SqlTransaction transaction, string commandText)
        {
            return ExecuteNonQuery(transaction, CommandType.Text, commandText, (SqlParameter[])null);
        }

        /// <summary>
        /// Execute a SqlCommand (that returns no resultset and takes no parameters) against the provided SqlTransaction. 
        /// </summary>
        /// <remarks>
        /// e.g.:  
        ///  int result = ExecuteNonQuery(trans, CommandType.StoredProcedure, "PublishOrders");
        /// </remarks>
        /// <param name="transaction">a valid SqlTransaction</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <returns>an int representing the number of rows affected by the command</returns>
        public static int ExecuteNonQuery(SqlTransaction transaction, CommandType commandType, string commandText)
        {
            //pass through the call providing null for the set of SqlParameters
            return ExecuteNonQuery(transaction, commandType, commandText, (SqlParameter[])null);
        }

        /// <summary>
        /// 带参数和参数的查询
        /// </summary>
        /// <param name="transaction"></param>
        /// <param name="commandText"></param>
        /// <param name="commandParameters"></param>
        /// <returns></returns>
        public static int ExecuteNonQuery(SqlTransaction transaction, string commandText, params SqlParameter[] commandParameters)
        {
            //pass through the call providing null for the set of SqlParameters
            return ExecuteNonQuery(transaction, CommandType.Text, commandText, commandParameters);
        }

        /// <summary>
        /// Execute a SqlCommand (that returns no resultset) against the specified SqlTransaction
        /// using the provided parameters.
        /// </summary>
        /// <remarks>
        /// e.g.:  
        ///  int result = ExecuteNonQuery(trans, CommandType.StoredProcedure, "GetOrders", new SqlParameter("@prodid", 24));
        /// </remarks>
        /// <param name="transaction">a valid SqlTransaction</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <param name="commandParameters">an array of SqlParamters used to execute the command</param>
        /// <returns>an int representing the number of rows affected by the command</returns>
        public static int ExecuteNonQuery(SqlTransaction transaction, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
        {
            if (transaction == null)
            {
                //create & open a SqlConnection, and dispose of it after we are done.
                using (SqlConnection cn = new SqlConnection(ConfigurationManager.AppSettings["ConnString"]))
                {
                    cn.Open();

                    //call the overload that takes a connection in place of the connection string
                    return ExecuteNonQuery(cn, commandType, commandText, commandParameters);
                }
            }
            else
            {
                //create a command and prepare it for execution
                SqlCommand cmd = new SqlCommand();
                PrepareCommand(cmd, transaction.Connection, transaction, commandType, commandText, commandParameters);

                //finally, execute the command.
                int retval = cmd.ExecuteNonQuery();

                // detach the SqlParameters from the command object, so they can be used again.
                cmd.Parameters.Clear();
                return retval;
            }
        }

        #endregion ExecuteNonQuery

        #region 执行SqlDataAdapter
        public static SqlDataAdapter ExecuteSqlDataAdapter(string commandText)
        {
            using (SqlConnection cn = new SqlConnection(ConfigurationManager.AppSettings["ConnString"]))
            {
                cn.Open();
                return ExecuteSqlDataAdapter(cn, commandText);
            }
        }

        public static SqlDataAdapter ExecuteSqlDataAdapter(SqlConnection connection, string commandText)
        {
            SqlDataAdapter myda = new SqlDataAdapter(commandText, connection);
            myda.SelectCommand.CommandTimeout = 180;
            connection.Close();
            return myda;
        }

        #endregion

        #region ExecuteDataSet

        /// <summary>
        /// 返回datataset 只需要传入查询语句
        /// </summary>
        /// <param name="commandText"></param>
        /// <returns></returns>
        public static DataSet ExecuteDataSet(string commandText)
        {
            //pass through the call providing null for the set of SqlParameters
            return ExecuteDataSet(ConfigurationManager.AppSettings["ConnString"], CommandType.Text, commandText, (SqlParameter[])null);
        }

        /// <summary>
        /// 带参数查询
        /// </summary>
        /// <param name="commandText"></param>
        /// <param name="commandParameters"></param>
        /// <returns></returns>
        public static DataSet ExecuteDataSet(string commandText, params SqlParameter[] commandParameters)
        {
            using (SqlConnection cn = new SqlConnection(ConfigurationManager.AppSettings["ConnString"]))
            {
                cn.Open();
                return ExecuteDataSet(cn, CommandType.Text, commandText, commandParameters);
            }
        }

        /// <summary>
        /// 执行存储过程 返回相应的dataset
        /// </summary>
        /// <param name="commandText">存储过程名字</param>
        /// <param name="commandType"></param>
        /// <param name="commandParameters"></param>
        /// <returns></returns>
        public static DataSet ExecuteDataSet(string commandText, CommandType commandType, params SqlParameter[] commandParameters)
        {
            using (SqlConnection cn = new SqlConnection(ConfigurationManager.AppSettings["ConnString"]))
            {
                cn.Open();
                return ExecuteDataSet(cn, commandType, commandText, commandParameters);
            }
        }

        /// <summary>
        /// Execute a SqlCommand (that returns a resultset and takes no parameters) against the database specified in 
        /// the connection string. 
        /// </summary>
        /// <remarks>
        /// e.g.:  
        ///  DataSet ds = ExecuteDataset(connString, CommandType.StoredProcedure, "GetOrders");
        /// </remarks>
        /// <param name="connectionString">a valid connection string for a SqlConnection</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <returns>a dataset containing the resultset generated by the command</returns>
        public static DataSet ExecuteDataSet(string connectionString, string commandText)
        {
            //pass through the call providing null for the set of SqlParameters
            return ExecuteDataSet(connectionString, CommandType.Text, commandText, (SqlParameter[])null);
        }

        /// <summary>
        /// Execute a SqlCommand (that returns a resultset and takes no parameters) against the database specified in 
        /// the connection string. 
        /// </summary>
        /// <remarks>
        /// e.g.:  
        ///  DataSet ds = ExecuteDataset(connString, CommandType.StoredProcedure, "GetOrders");
        /// </remarks>
        /// <param name="connectionString">a valid connection string for a SqlConnection</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <returns>a dataset containing the resultset generated by the command</returns>
        public static DataSet ExecuteDataSet(string connectionString, CommandType commandType, string commandText)
        {
            //pass through the call providing null for the set of SqlParameters
            return ExecuteDataSet(connectionString, commandType, commandText, (SqlParameter[])null);
        }

        /// <summary>
        /// Execute a SqlCommand (that returns a resultset) against the database specified in the connection string 
        /// using the provided parameters.
        /// </summary>
        /// <remarks>
        /// e.g.:  
        ///  DataSet ds = ExecuteDataset(connString, CommandType.StoredProcedure, "GetOrders", new SqlParameter("@prodid", 24));
        /// </remarks>
        /// <param name="connectionString">a valid connection string for a SqlConnection</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <param name="commandParameters">an array of SqlParamters used to execute the command</param>
        /// <returns>a dataset containing the resultset generated by the command</returns>
        public static DataSet ExecuteDataSet(string connectionString, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
        {
            //create & open a SqlConnection, and dispose of it after we are done.
            try
            {
                using (SqlConnection cn = new SqlConnection(connectionString))
                {
                    cn.Open();


                    //call the overload that takes a connection in place of the connection string
                    return ExecuteDataSet(cn, commandType, commandText, commandParameters);
                }
            }
            catch (Exception e)
            {

                throw e;
            }
        }

        /// <summary>
        /// 返回datataset 只需要传入查询语句
        /// </summary>
        /// <param name="commandText"></param>
        /// <returns></returns>
        public static DataSet ExecuteDataSet(SqlConnection connection, string commandText)
        {
            //pass through the call providing null for the set of SqlParameters
            return ExecuteDataSet(connection, CommandType.Text, commandText);
        }

        /// <summary>
        /// Execute a SqlCommand (that returns a resultset and takes no parameters) against the provided SqlConnection. 
        /// </summary>
        /// <remarks>
        /// e.g.:  
        ///  DataSet ds = ExecuteDataset(conn, CommandType.StoredProcedure, "GetOrders");
        /// </remarks>
        /// <param name="connection">a valid SqlConnection</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <returns>a dataset containing the resultset generated by the command</returns>
        public static DataSet ExecuteDataSet(SqlConnection connection, CommandType commandType, string commandText)
        {
            //pass through the call providing null for the set of SqlParameters
            return ExecuteDataSet(connection, commandType, commandText, (SqlParameter[])null);
        }

        /// <summary>
        /// Execute a SqlCommand (that returns a resultset) against the specified SqlConnection 
        /// using the provided parameters.
        /// </summary>
        /// <remarks>
        /// e.g.:  
        ///  DataSet ds = ExecuteDataset(conn, CommandType.StoredProcedure, "GetOrders", new SqlParameter("@prodid", 24));
        /// </remarks>
        /// <param name="connection">a valid SqlConnection</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <param name="commandParameters">an array of SqlParamters used to execute the command</param>
        /// <returns>a dataset containing the resultset generated by the command</returns>
        public static DataSet ExecuteDataSet(SqlConnection connection, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
        {
            //create a command and prepare it for execution
            SqlCommand cmd = new SqlCommand();
            PrepareCommand(cmd, connection, (SqlTransaction)null, commandType, commandText, commandParameters);

            //create the DataAdapter & DataSet
            SqlDataAdapter da = new SqlDataAdapter(cmd);
            DataSet ds = new DataSet();

            //fill the DataSet using default values for DataTable names, etc.
            da.Fill(ds);

            // detach the SqlParameters from the command object, so they can be used again.   
            cmd.Parameters.Clear();

            if (connection.State == ConnectionState.Open)
                connection.Close();
            //return the dataset
            return ds;
        }

        /// <summary>
        /// s事务中执行返回dataset
        /// </summary>
        /// <param name="transaction"></param>
        /// <param name="commandText"></param>
        /// <returns></returns>
        public static DataSet ExecuteDataSet(SqlTransaction transaction, string commandText)
        {
            //pass through the call providing null for the set of SqlParameters
            return ExecuteDataSet(transaction, CommandType.Text, commandText, (SqlParameter[])null);
        }

        /// <summary>
        /// Execute a SqlCommand (that returns a resultset and takes no parameters) against the provided SqlTransaction. 
        /// </summary>
        /// <remarks>
        /// e.g.:  
        ///  DataSet ds = ExecuteDataset(trans, CommandType.StoredProcedure, "GetOrders");
        /// </remarks>
        /// <param name="transaction">a valid SqlTransaction</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <returns>a dataset containing the resultset generated by the command</returns>
        public static DataSet ExecuteDataSet(SqlTransaction transaction, CommandType commandType, string commandText)
        {
            //pass through the call providing null for the set of SqlParameters
            return ExecuteDataSet(transaction, commandType, commandText, (SqlParameter[])null);
        }

        /// <summary>
        /// 事务中返回dataset 可带参数
        /// </summary>
        /// <param name="transaction"></param>
        /// <param name="commandText"></param>
        /// <param name="commandParameters"></param>
        /// <returns></returns>
        public static DataSet ExecuteDataSet(SqlTransaction transaction, string commandText, params SqlParameter[] commandParameters)
        {
            //pass through the call providing null for the set of SqlParameters
            return ExecuteDataSet(transaction, CommandType.Text, commandText, (SqlParameter[])null);
        }

        /// <summary>
        /// Execute a SqlCommand (that returns a resultset) against the specified SqlTransaction
        /// using the provided parameters.
        /// </summary>
        /// <remarks>
        /// e.g.:  
        ///  DataSet ds = ExecuteDataset(trans, CommandType.StoredProcedure, "GetOrders", new SqlParameter("@prodid", 24));
        /// </remarks>
        /// <param name="transaction">a valid SqlTransaction</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <param name="commandParameters">an array of SqlParamters used to execute the command</param>
        /// <returns>a dataset containing the resultset generated by the command</returns>
        public static DataSet ExecuteDataSet(SqlTransaction transaction, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
        {
            if (transaction == null)
            {
                //create & open a SqlConnection, and dispose of it after we are done.
                using (SqlConnection cn = new SqlConnection(ConfigurationManager.AppSettings["ConnString"]))
                {
                    cn.Open();

                    //call the overload that takes a connection in place of the connection string
                    return ExecuteDataSet(cn, commandType, commandText, commandParameters);
                }
            }
            else
            {
                //create a command and prepare it for execution
                SqlCommand cmd = new SqlCommand();
                PrepareCommand(cmd, transaction.Connection, transaction, commandType, commandText, commandParameters);

                //create the DataAdapter & DataSet
                SqlDataAdapter da = new SqlDataAdapter(cmd);
                DataSet ds = new DataSet();

                //fill the DataSet using default values for DataTable names, etc.
                da.Fill(ds);

                // detach the SqlParameters from the command object, so they can be used again.
                cmd.Parameters.Clear();

                //return the dataset
                return ds;
            }
        }

        #endregion ExecuteDataSet

        #region ExecuteDataTable

        /// <summary>
        /// 连接数据库
        /// </summary>
        /// <param name="commandText"></param>
        /// <returns></returns>
        public static DataTable ExecuteDataTable(string commandText)
        {
            //pass through the call providing null for the set of SqlParameters
            return ExecuteDataTable(ConfigurationManager.AppSettings["ConnString"], CommandType.Text, commandText, (SqlParameter[])null);
        }

        /// <summary>
        /// 连接数据库
        /// </summary>
        /// <param name="commandText"></param>
        /// <returns></returns>
        public static DataTable ExecuteDataTable(string commandText, params SqlParameter[] commandParameters)
        {
            //pass through the call providing null for the set of SqlParameters
            return ExecuteDataTable(ConfigurationManager.AppSettings["ConnString"], CommandType.Text, commandText, commandParameters);
        }

        /// <summary>
        /// Execute a SqlCommand (that returns a resultset and takes no parameters) against the database specified in 
        /// the connection string. 
        /// </summary>
        /// <remarks>
        /// e.g.:  
        ///  DataTable dt = ExecuteDataTable(connString, CommandType.StoredProcedure, "GetOrders");
        /// </remarks>
        /// <param name="connectionString">a valid connection string for a SqlConnection</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <returns>a DataTable containing the resultset generated by the command</returns>
        public static DataTable ExecuteDataTable(string connectionString, CommandType commandType, string commandText)
        {
            //pass through the call providing null for the set of SqlParameters
            return ExecuteDataTable(connectionString, commandType, commandText, (SqlParameter[])null);
        }

        /// <summary>
        /// Execute a SqlCommand (that returns a resultset) against the database specified in the connection string 
        /// using the provided parameters.
        /// </summary>
        /// <remarks>
        /// e.g.:  
        ///  DataTable dt = ExecuteDataTable(connString, CommandType.StoredProcedure, "GetOrders", new SqlParameter("@prodid", 24));
        /// </remarks>
        /// <param name="connectionString">a valid connection string for a SqlConnection</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <param name="commandParameters">an array of SqlParamters used to execute the command</param>
        /// <returns>a DataTable containing the resultset generated by the command</returns>
        public static DataTable ExecuteDataTable(string connectionString, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
        {
            //create & open a SqlConnection, and dispose of it after we are done.
            using (SqlConnection cn = new SqlConnection(connectionString))
            {
                cn.Open();

                //call the overload that takes a connection in place of the connection string
                return ExecuteDataTable(cn, commandType, commandText, commandParameters);
            }
        }

        /// <summary>
        /// 连接数据库
        /// </summary>
        /// <param name="commandText"></param>
        /// <returns></returns>
        public static DataTable ExecuteDataTable(SqlConnection connection, string commandText)
        {
            //pass through the call providing null for the set of SqlParameters
            return ExecuteDataTable(connection, CommandType.Text, commandText);
        }

        /// <summary>
        /// Execute a SqlCommand (that returns a resultset and takes no parameters) against the provided SqlConnection. 
        /// </summary>
        /// <remarks>
        /// e.g.:  
        ///  DataTable dt = ExecuteDataTable(conn, CommandType.StoredProcedure, "GetOrders");
        /// </remarks>
        /// <param name="connection">a valid SqlConnection</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <returns>a DataTable containing the resultset generated by the command</returns>
        public static DataTable ExecuteDataTable(SqlConnection connection, CommandType commandType, string commandText)
        {
            //pass through the call providing null for the set of SqlParameters
            return ExecuteDataTable(connection, commandType, commandText, (SqlParameter[])null);
        }

        /// <summary>
        /// Execute a SqlCommand (that returns a resultset) against the specified SqlConnection 
        /// using the provided parameters.
        /// </summary>
        /// <remarks>
        /// e.g.:  
        ///  DataTable dt = ExecuteDataTable(conn, CommandType.StoredProcedure, "GetOrders", new SqlParameter("@prodid", 24));
        /// </remarks>
        /// <param name="connection">a valid SqlConnection</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <param name="commandParameters">an array of SqlParamters used to execute the command</param>
        /// <returns>a DataTable containing the resultset generated by the command</returns>
        public static DataTable ExecuteDataTable(SqlConnection connection, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
        {
            //create a command and prepare it for execution
            SqlCommand cmd = new SqlCommand();
            PrepareCommand(cmd, connection, (SqlTransaction)null, commandType, commandText, commandParameters);

            //create the DataAdapter & DataTable
            SqlDataAdapter da = new SqlDataAdapter(cmd);
            DataTable dt = new DataTable();

            //fill the DataTable using default values for DataTable names, etc.
            da.Fill(dt);

            // detach the SqlParameters from the command object, so they can be used again.   
            cmd.Parameters.Clear();

            if (connection.State == ConnectionState.Open)
                connection.Close();
            //return the DataTable
            return dt;
        }

        /// <summary>
        /// Execute a SqlCommand (that returns a resultset and takes no parameters) against the provided SqlTransaction. 
        /// </summary>
        /// <remarks>
        /// e.g.:  
        ///  DataTable dt = ExecuteDataTable(trans, CommandType.StoredProcedure, "GetOrders");
        /// </remarks>
        /// <param name="transaction">a valid SqlTransaction</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <returns>a DataTable containing the resultset generated by the command</returns>
        public static DataTable ExecuteDataTable(SqlTransaction transaction, string commandText)
        {
            //pass through the call providing null for the set of SqlParameters
            return ExecuteDataTable(transaction, CommandType.Text, commandText, (SqlParameter[])null);
        }

        /// <summary>
        /// Execute a SqlCommand (that returns a resultset and takes no parameters) against the provided SqlTransaction. 
        /// </summary>
        /// <remarks>
        /// e.g.:  
        ///  DataTable dt = ExecuteDataTable(trans, CommandType.StoredProcedure, "GetOrders");
        /// </remarks>
        /// <param name="transaction">a valid SqlTransaction</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <returns>a DataTable containing the resultset generated by the command</returns>
        public static DataTable ExecuteDataTable(SqlTransaction transaction, CommandType commandType, string commandText)
        {
            //pass through the call providing null for the set of SqlParameters
            return ExecuteDataTable(transaction, commandType, commandText, (SqlParameter[])null);
        }

        /// <summary>
        /// Execute a SqlCommand (that returns a resultset) against the specified SqlTransaction
        /// using the provided parameters.
        /// </summary>
        /// <remarks>
        /// e.g.:  
        ///  DataTable dt = ExecuteDataTable(trans, CommandType.StoredProcedure, "GetOrders", new SqlParameter("@prodid", 24));
        /// </remarks>
        /// <param name="transaction">a valid SqlTransaction</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <param name="commandParameters">an array of SqlParamters used to execute the command</param>
        /// <returns>a DataTable containing the resultset generated by the command</returns>
        public static DataTable ExecuteDataTable(SqlTransaction transaction, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
        {
            if (transaction == null)
            {
                //create & open a SqlConnection, and dispose of it after we are done.
                using (SqlConnection cn = new SqlConnection(ConfigurationManager.AppSettings["ConnString"]))
                {
                    cn.Open();

                    //call the overload that takes a connection in place of the connection string
                    return ExecuteDataTable(cn, commandType, commandText, commandParameters);
                }
            }
            else
            {
                //create a command and prepare it for execution
                SqlCommand cmd = new SqlCommand();
                PrepareCommand(cmd, transaction.Connection, transaction, commandType, commandText, commandParameters);

                //create the DataAdapter & DataTable
                SqlDataAdapter da = new SqlDataAdapter(cmd);
                DataTable dt = new DataTable();

                //fill the DataTable using default values for DataTable names, etc.
                da.Fill(dt);

                // detach the SqlParameters from the command object, so they can be used again.
                cmd.Parameters.Clear();

                //return the DataTable
                return dt;
            }
        }

        #endregion ExecuteDataTable

        #region ExecuteReader

        /// <summary>
        /// this enum is used to indicate whether the connection was provided by the caller, or created by SqlHelper, so that
        /// we can set the appropriate CommandBehavior when calling ExecuteReader()
        /// </summary>
        private enum SqlConnectionOwnership
        {
            /// <summary>Connection is owned and managed by SqlHelper</summary>
            Internal,
            /// <summary>Connection is owned and managed by the caller</summary>
            External
        }

        /// <summary>
        /// 返回SqlDataReader 只是传入一条sql语句
        /// </summary>
        /// <param name="commandText">sql语句</param>
        /// <returns></returns>
        public static SqlDataReader ExecuteReader(string commandText)
        {
            return ExecuteReader(ConfigurationManager.AppSettings["ConnString"], CommandType.Text, commandText, (SqlParameter[])null);
        }

        /// <summary>
        /// 返回SqlDataReader 只是传入一条sql语句和相应的参数
        /// </summary>
        /// <param name="commandText"></param>
        /// <param name="commandParameters"></param>
        /// <returns></returns>
        public static SqlDataReader ExecuteReader(string commandText, params SqlParameter[] commandParameters)
        {
            return ExecuteReader(ConfigurationManager.AppSettings["ConnString"], CommandType.Text, commandText, commandParameters);
        }

        /// <summary>
        /// 返回SqlDataReader 只是传入一条sql语句和相应的参数
        /// </summary>
        /// <param name="commandText"></param>
        /// <param name="commandParameters"></param>
        /// <returns></returns>
        public static SqlDataReader ExecuteReader(string commandText, CommandType commandType, params SqlParameter[] commandParameters)
        {
            return ExecuteReader(ConfigurationManager.AppSettings["ConnString"], commandType, commandText, commandParameters);
        }

        /// <summary>
        /// Execute a SqlCommand (that returns a resultset and takes no parameters) against the database specified in 
        /// the connection string. 
        /// </summary>
        /// <remarks>
        /// e.g.:  
        ///  SqlDataReader dr = ExecuteReader(connString, CommandType.StoredProcedure, "GetOrders");
        /// </remarks>
        /// <param name="connectionString">a valid connection string for a SqlConnection</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <returns>a SqlDataReader containing the resultset generated by the command</returns>
        public static SqlDataReader ExecuteReader(string connectionString, string commandText)
        {
            //pass through the call providing null for the set of SqlParameters
            return ExecuteReader(connectionString, CommandType.Text, commandText, (SqlParameter[])null);
        }

        /// <summary>
        /// Execute a SqlCommand (that returns a resultset and takes no parameters) against the database specified in 
        /// the connection string. 
        /// </summary>
        /// <remarks>
        /// e.g.:  
        ///  SqlDataReader dr = ExecuteReader(connString, CommandType.StoredProcedure, "GetOrders");
        /// </remarks>
        /// <param name="connectionString">a valid connection string for a SqlConnection</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <returns>a SqlDataReader containing the resultset generated by the command</returns>
        public static SqlDataReader ExecuteReader(string connectionString, CommandType commandType, string commandText)
        {
            //pass through the call providing null for the set of SqlParameters
            return ExecuteReader(connectionString, commandType, commandText, (SqlParameter[])null);
        }

        /// <summary>
        /// Execute a SqlCommand (that returns a resultset) against the database specified in the connection string 
        /// using the provided parameters.
        /// </summary>
        /// <remarks>
        /// e.g.:  
        ///  SqlDataReader dr = ExecuteReader(connString, CommandType.StoredProcedure, "GetOrders", new SqlParameter("@prodid", 24));
        /// </remarks>
        /// <param name="connectionString">a valid connection string for a SqlConnection</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <param name="commandParameters">an array of SqlParamters used to execute the command</param>
        /// <returns>a SqlDataReader containing the resultset generated by the command</returns>
        public static SqlDataReader ExecuteReader(string connectionString, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
        {
            //create & open a SqlConnection
            SqlConnection cn = new SqlConnection(connectionString);
            cn.Open();

            try
            {
                //call the private overload that takes an internally owned connection in place of the connection string
                return ExecuteReader(cn, null, commandType, commandText, commandParameters, SqlConnectionOwnership.Internal);
            }
            catch
            {
                //if we fail to return the SqlDatReader, we need to close the connection ourselves
                cn.Close();
                throw;
            }
        }

        /// <summary>
        /// 返回SqlDataReader 只是传入一条sql语句
        /// </summary>
        /// <param name="commandText">sql语句</param>
        /// <returns></returns>
        public static SqlDataReader ExecuteReader(SqlConnection connection, string commandText)
        {
            return ExecuteReader(connection, CommandType.Text, commandText, (SqlParameter[])null);
        }

        /// <summary>
        /// Execute a SqlCommand (that returns a resultset and takes no parameters) against the provided SqlConnection. 
        /// </summary>
        /// <remarks>
        /// e.g.:  
        ///  SqlDataReader dr = ExecuteReader(conn, CommandType.StoredProcedure, "GetOrders");
        /// </remarks>
        /// <param name="connection">a valid SqlConnection</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <returns>a SqlDataReader containing the resultset generated by the command</returns>
        public static SqlDataReader ExecuteReader(SqlConnection connection, CommandType commandType, string commandText)
        {
            //pass through the call providing null for the set of SqlParameters
            return ExecuteReader(connection, commandType, commandText, (SqlParameter[])null);
        }

        /// <summary>
        /// Execute a SqlCommand (that returns a resultset) against the specified SqlConnection 
        /// using the provided parameters.
        /// </summary>
        /// <remarks>
        /// e.g.:  
        ///  SqlDataReader dr = ExecuteReader(conn, CommandType.StoredProcedure, "GetOrders", new SqlParameter("@prodid", 24));
        /// </remarks>
        /// <param name="connection">a valid SqlConnection</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <param name="commandParameters">an array of SqlParamters used to execute the command</param>
        /// <returns>a SqlDataReader containing the resultset generated by the command</returns>
        public static SqlDataReader ExecuteReader(SqlConnection connection, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
        {
            //pass through the call to the private overload using a null transaction value and an externally owned connection
            return ExecuteReader(connection, (SqlTransaction)null, commandType, commandText, commandParameters, SqlConnectionOwnership.External);
        }

        /// <summary>
        /// Create and prepare a SqlCommand, and call ExecuteReader with the appropriate CommandBehavior.
        /// </summary>
        /// <remarks>
        /// If we created and opened the connection, we want the connection to be closed when the DataReader is closed.
        /// 
        /// If the caller provided the connection, we want to leave it to them to manage.
        /// </remarks>
        /// <param name="connection">a valid SqlConnection, on which to execute this command</param>
        /// <param name="transaction">a valid SqlTransaction, or 'null'</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <param name="commandParameters">an array of SqlParameters to be associated with the command or 'null' if no parameters are required</param>
        /// <param name="connectionOwnership">indicates whether the connection parameter was provided by the caller, or created by SqlHelper</param>
        /// <returns>SqlDataReader containing the results of the command</returns>
        private static SqlDataReader ExecuteReader(SqlConnection connection, SqlTransaction transaction, CommandType commandType, string commandText, SqlParameter[] commandParameters, SqlConnectionOwnership connectionOwnership)
        {
            //create a command and prepare it for execution
            SqlCommand cmd = new SqlCommand();
            PrepareCommand(cmd, connection, transaction, commandType, commandText, commandParameters);

            //create a reader
            SqlDataReader dr;

            // call ExecuteReader with the appropriate CommandBehavior
            if (connectionOwnership == SqlConnectionOwnership.External)
                dr = cmd.ExecuteReader();
            else
                dr = cmd.ExecuteReader(CommandBehavior.CloseConnection);

            // detach the SqlParameters from the command object, so they can be used again.
            cmd.Parameters.Clear();

            return dr;
        }

        /// <summary>
        /// Execute a SqlCommand (that returns a resultset and takes no parameters) against the provided SqlTransaction. 
        /// </summary>
        /// <remarks>
        /// e.g.:  
        ///  SqlDataReader dr = ExecuteReader(trans, CommandType.StoredProcedure, "GetOrders");
        /// </remarks>
        /// <param name="transaction">a valid SqlTransaction</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <returns>a SqlDataReader containing the resultset generated by the command</returns>
        public static SqlDataReader ExecuteReader(SqlTransaction transaction, CommandType commandType, string commandText)
        {
            //pass through the call providing null for the set of SqlParameters
            return ExecuteReader(transaction, commandType, commandText, (SqlParameter[])null);
        }

        /// <summary>
        /// Execute a SqlCommand (that returns a resultset) against the specified SqlTransaction
        /// using the provided parameters.
        /// </summary>
        /// <remarks>
        /// e.g.:  
        ///   SqlDataReader dr = ExecuteReader(trans, CommandType.StoredProcedure, "GetOrders", new SqlParameter("@prodid", 24));
        /// </remarks>
        /// <param name="transaction">a valid SqlTransaction</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <param name="commandParameters">an array of SqlParamters used to execute the command</param>
        /// <returns>a SqlDataReader containing the resultset generated by the command</returns>
        public static SqlDataReader ExecuteReader(SqlTransaction transaction, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
        {
            if (transaction == null)
            {
                //create & open a SqlConnection
                SqlConnection cn = new SqlConnection(ConfigurationManager.AppSettings["ConnString"]);
                cn.Open();

                try
                {
                    //call the private overload that takes an internally owned connection in place of the connection string
                    return ExecuteReader(cn, null, commandType, commandText, commandParameters, SqlConnectionOwnership.Internal);
                }
                catch
                {
                    //if we fail to return the SqlDatReader, we need to close the connection ourselves
                    cn.Close();
                    throw;
                }
            }
            else
                //pass through to private overload, indicating that the connection is owned by the caller
                return ExecuteReader(transaction.Connection, transaction, commandType, commandText, commandParameters, SqlConnectionOwnership.External);
        }

        #endregion ExecuteReader

        #region ExecuteScalar

        /// <summary>
        /// 返回ExecuteScalar 只是传入一条sql语句
        /// </summary>
        /// <param name="commandText">sql语句</param>
        /// <returns></returns>
        public static object ExecuteScalar(string commandText)
        {
            return ExecuteScalar(ConfigurationManager.AppSettings["ConnString"], CommandType.Text, commandText, (SqlParameter[])null);
        }

        public static object ExecuteScalar(string commandText, params SqlParameter[] commandParameters)
        {
            return ExecuteScalar(ConfigurationManager.AppSettings["ConnString"], CommandType.Text, commandText, commandParameters);
        }

        /// <summary>
        /// Execute a SqlCommand (that returns a 1x1 resultset and takes no parameters) against the database specified in 
        /// the connection string. 
        /// </summary>
        /// <remarks>
        /// e.g.:  
        ///  int orderCount = (int)ExecuteScalar(connString, CommandType.StoredProcedure, "GetOrderCount");
        /// </remarks>
        /// <param name="connectionString">a valid connection string for a SqlConnection</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <returns>an object containing the value in the 1x1 resultset generated by the command</returns>
        public static object ExecuteScalar(string connectionString, CommandType commandType, string commandText)
        {
            //pass through the call providing null for the set of SqlParameters
            return ExecuteScalar(connectionString, commandType, commandText, (SqlParameter[])null);
        }

        /// <summary>
        /// Execute a SqlCommand (that returns a 1x1 resultset) against the database specified in the connection string 
        /// using the provided parameters.
        /// </summary>
        /// <remarks>
        /// e.g.:  
        ///  int orderCount = (int)ExecuteScalar(connString, CommandType.StoredProcedure, "GetOrderCount", new SqlParameter("@prodid", 24));
        /// </remarks>
        /// <param name="connectionString">a valid connection string for a SqlConnection</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <param name="commandParameters">an array of SqlParamters used to execute the command</param>
        /// <returns>an object containing the value in the 1x1 resultset generated by the command</returns>
        public static object ExecuteScalar(string connectionString, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
        {
            //create & open a SqlConnection, and dispose of it after we are done.
            using (SqlConnection cn = new SqlConnection(connectionString))
            {
                cn.Open();

                //call the overload that takes a connection in place of the connection string
                return ExecuteScalar(cn, commandType, commandText, commandParameters);
            }
        }

        /// <summary>
        /// 返回ExecuteScalar 只是传入一条sql语句
        /// </summary>
        /// <param name="commandText">sql语句</param>
        /// <returns></returns>
        public static object ExecuteScalar(SqlConnection connection, string commandText)
        {
            return ExecuteScalar(connection, CommandType.Text, commandText, (SqlParameter[])null);
        }

        /// <summary>
        /// Execute a SqlCommand (that returns a 1x1 resultset and takes no parameters) against the provided SqlConnection. 
        /// </summary>
        /// <remarks>
        /// e.g.:  
        ///  int orderCount = (int)ExecuteScalar(conn, CommandType.StoredProcedure, "GetOrderCount");
        /// </remarks>
        /// <param name="connection">a valid SqlConnection</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <returns>an object containing the value in the 1x1 resultset generated by the command</returns>
        public static object ExecuteScalar(SqlConnection connection, CommandType commandType, string commandText)
        {
            //pass through the call providing null for the set of SqlParameters
            return ExecuteScalar(connection, commandType, commandText, (SqlParameter[])null);
        }

        /// <summary>
        /// Execute a SqlCommand (that returns a 1x1 resultset) against the specified SqlConnection 
        /// using the provided parameters.
        /// </summary>
        /// <remarks>
        /// e.g.:  
        ///  int orderCount = (int)ExecuteScalar(conn, CommandType.StoredProcedure, "GetOrderCount", new SqlParameter("@prodid", 24));
        /// </remarks>
        /// <param name="connection">a valid SqlConnection</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <param name="commandParameters">an array of SqlParamters used to execute the command</param>
        /// <returns>an object containing the value in the 1x1 resultset generated by the command</returns>
        public static object ExecuteScalar(SqlConnection connection, string commandText, params SqlParameter[] commandParameters)
        {
            //pass through the call providing null for the set of SqlParameters
            return ExecuteScalar(connection, CommandType.Text, commandText, commandParameters);
        }

        /// <summary>
        /// Execute a SqlCommand (that returns a 1x1 resultset) against the specified SqlConnection 
        /// using the provided parameters.
        /// </summary>
        /// <remarks>
        /// e.g.:  
        ///  int orderCount = (int)ExecuteScalar(conn, CommandType.StoredProcedure, "GetOrderCount", new SqlParameter("@prodid", 24));
        /// </remarks>
        /// <param name="connection">a valid SqlConnection</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <param name="commandParameters">an array of SqlParamters used to execute the command</param>
        /// <returns>an object containing the value in the 1x1 resultset generated by the command</returns>
        public static object ExecuteScalar(SqlConnection connection, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
        {
            //create a command and prepare it for execution
            SqlCommand cmd = new SqlCommand();
            PrepareCommand(cmd, connection, (SqlTransaction)null, commandType, commandText, commandParameters);

            //execute the command & return the results
            object retval = cmd.ExecuteScalar();

            // detach the SqlParameters from the command object, so they can be used again.
            cmd.Parameters.Clear();
            if (connection.State == ConnectionState.Open)
                connection.Close();
            return retval;

        }

        /// <summary>
        /// Execute a SqlCommand (that returns a 1x1 resultset and takes no parameters) against the provided SqlTransaction. 
        /// </summary>
        /// <remarks>
        /// e.g.:  
        ///  int orderCount = (int)ExecuteScalar(trans, CommandType.StoredProcedure, "GetOrderCount");
        /// </remarks>
        /// <param name="transaction">a valid SqlTransaction</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <returns>an object containing the value in the 1x1 resultset generated by the command</returns>
        public static object ExecuteScalar(SqlTransaction transaction, string commandText)
        {
            //pass through the call providing null for the set of SqlParameters
            return ExecuteScalar(transaction, CommandType.Text, commandText, (SqlParameter[])null);
        }

        /// <summary>
        /// Execute a SqlCommand (that returns a 1x1 resultset and takes no parameters) against the provided SqlTransaction. 
        /// </summary>
        /// <remarks>
        /// e.g.:  
        ///  int orderCount = (int)ExecuteScalar(trans, CommandType.StoredProcedure, "GetOrderCount");
        /// </remarks>
        /// <param name="transaction">a valid SqlTransaction</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <returns>an object containing the value in the 1x1 resultset generated by the command</returns>
        public static object ExecuteScalar(SqlTransaction transaction, CommandType commandType, string commandText)
        {
            //pass through the call providing null for the set of SqlParameters
            return ExecuteScalar(transaction, commandType, commandText, (SqlParameter[])null);
        }

        /// <summary>
        /// Execute a SqlCommand (that returns a 1x1 resultset) against the specified SqlTransaction
        /// using the provided parameters.
        /// </summary>
        /// <remarks>
        /// e.g.:  
        ///  int orderCount = (int)ExecuteScalar(trans, CommandType.StoredProcedure, "GetOrderCount", new SqlParameter("@prodid", 24));
        /// </remarks>
        /// <param name="transaction">a valid SqlTransaction</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <param name="commandParameters">an array of SqlParamters used to execute the command</param>
        /// <returns>an object containing the value in the 1x1 resultset generated by the command</returns>
        public static object ExecuteScalar(SqlTransaction transaction, string commandText, params SqlParameter[] commandParameters)
        {
            return ExecuteScalar(transaction, CommandType.Text, commandText, commandParameters);
        }

        /// <summary>
        /// Execute a SqlCommand (that returns a 1x1 resultset) against the specified SqlTransaction
        /// using the provided parameters.
        /// </summary>
        /// <remarks>
        /// e.g.:  
        ///  int orderCount = (int)ExecuteScalar(trans, CommandType.StoredProcedure, "GetOrderCount", new SqlParameter("@prodid", 24));
        /// </remarks>
        /// <param name="transaction">a valid SqlTransaction</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <param name="commandParameters">an array of SqlParamters used to execute the command</param>
        /// <returns>an object containing the value in the 1x1 resultset generated by the command</returns>
        public static object ExecuteScalar(SqlTransaction transaction, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
        {
            if (transaction == null)
            {
                //create & open a SqlConnection, and dispose of it after we are done.
                using (SqlConnection cn = new SqlConnection(ConfigurationManager.AppSettings["ConnString"]))
                {
                    cn.Open();

                    //call the overload that takes a connection in place of the connection string
                    return ExecuteScalar(cn, commandType, commandText, commandParameters);
                }
            }
            else
            {
                //create a command and prepare it for execution
                SqlCommand cmd = new SqlCommand();
                PrepareCommand(cmd, transaction.Connection, transaction, commandType, commandText, commandParameters);

                //execute the command & return the results
                object retval = cmd.ExecuteScalar();

                // detach the SqlParameters from the command object, so they can be used again.
                cmd.Parameters.Clear();
                return retval;
            }
        }

        #endregion ExecuteScalar

        #region ExecuteXmlReader

        /// <summary>
        /// Execute a SqlCommand (that returns a resultset and takes no parameters) against the provided SqlConnection. 
        /// </summary>
        /// <remarks>
        /// e.g.:  
        ///  XmlReader r = ExecuteXmlReader(conn, CommandType.StoredProcedure, "GetOrders");
        /// </remarks>
        /// <param name="connection">a valid SqlConnection</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command using "FOR XML AUTO"</param>
        /// <returns>an XmlReader containing the resultset generated by the command</returns>
        public static XmlReader ExecuteXmlReader(SqlConnection connection, CommandType commandType, string commandText)
        {
            //pass through the call providing null for the set of SqlParameters
            return ExecuteXmlReader(connection, commandType, commandText, (SqlParameter[])null);
        }

        /// <summary>
        /// Execute a SqlCommand (that returns a resultset) against the specified SqlConnection 
        /// using the provided parameters.
        /// </summary>
        /// <remarks>
        /// e.g.:  
        ///  XmlReader r = ExecuteXmlReader(conn, CommandType.StoredProcedure, "GetOrders", new SqlParameter("@prodid", 24));
        /// </remarks>
        /// <param name="connection">a valid SqlConnection</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command using "FOR XML AUTO"</param>
        /// <param name="commandParameters">an array of SqlParamters used to execute the command</param>
        /// <returns>an XmlReader containing the resultset generated by the command</returns>
        public static XmlReader ExecuteXmlReader(SqlConnection connection, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
        {
            //create a command and prepare it for execution
            SqlCommand cmd = new SqlCommand();
            PrepareCommand(cmd, connection, (SqlTransaction)null, commandType, commandText, commandParameters);

            //create the DataAdapter & DataSet
            XmlReader retval = cmd.ExecuteXmlReader();

            // detach the SqlParameters from the command object, so they can be used again.
            cmd.Parameters.Clear();
            if (connection.State == ConnectionState.Open)
                connection.Close();
            return retval;

        }

        /// <summary>
        /// Execute a SqlCommand (that returns a resultset and takes no parameters) against the provided SqlTransaction. 
        /// </summary>
        /// <remarks>
        /// e.g.:  
        ///  XmlReader r = ExecuteXmlReader(trans, CommandType.StoredProcedure, "GetOrders");
        /// </remarks>
        /// <param name="transaction">a valid SqlTransaction</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command using "FOR XML AUTO"</param>
        /// <returns>an XmlReader containing the resultset generated by the command</returns>
        public static XmlReader ExecuteXmlReader(SqlTransaction transaction, CommandType commandType, string commandText)
        {
            //pass through the call providing null for the set of SqlParameters
            return ExecuteXmlReader(transaction, commandType, commandText, (SqlParameter[])null);
        }

        /// <summary>
        /// Execute a SqlCommand (that returns a resultset) against the specified SqlTransaction
        /// using the provided parameters.
        /// </summary>
        /// <remarks>
        /// e.g.:  
        ///  XmlReader r = ExecuteXmlReader(trans, CommandType.StoredProcedure, "GetOrders", new SqlParameter("@prodid", 24));
        /// </remarks>
        /// <param name="transaction">a valid SqlTransaction</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command using "FOR XML AUTO"</param>
        /// <param name="commandParameters">an array of SqlParamters used to execute the command</param>
        /// <returns>an XmlReader containing the resultset generated by the command</returns>
        public static XmlReader ExecuteXmlReader(SqlTransaction transaction, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
        {
            //create a command and prepare it for execution
            SqlCommand cmd = new SqlCommand();
            PrepareCommand(cmd, transaction.Connection, transaction, commandType, commandText, commandParameters);

            //create the DataAdapter & DataSet
            XmlReader retval = cmd.ExecuteXmlReader();

            // detach the SqlParameters from the command object, so they can be used again.
            cmd.Parameters.Clear();
            return retval;

        }

 

        #endregion ExecuteXmlReader

        #region CreateSqlConnection
        public static SqlConnection CreateSqlConnection(string connectionString)
        {
            //create & open a SqlConnection
            SqlConnection cn = new SqlConnection(connectionString);
            try
            {
                cn.Open();
            }
            catch
            {
                //if we fail to return the SqlTransaction, we need to close the connection ourselves
                cn.Close();
                throw;
            }
            return cn;
        }


        public static SqlConnection CreateSqlConnection()
        {
            return CreateSqlConnection(ConfigurationManager.AppSettings["ConnString"]);
        }
        #endregion

        #region ExecuteSqlCommand

        public static SqlCommand ExecuteSqlCommand()
        {
            return ExecuteSqlCommand("", ConfigurationManager.AppSettings["ConnString"]);
        }

        public static SqlCommand ExecuteSqlCommand(string CmdText)
        {
            return ExecuteSqlCommand(CmdText, ConfigurationManager.AppSettings["ConnString"]);
        }

        public static SqlCommand ExecuteSqlCommand(SqlConnection cn)
        {
            if (cn.State == ConnectionState.Closed || cn.State == ConnectionState.Broken)
                cn.Open();
            try
            {
                return new SqlCommand("", cn);
            }
            catch
            {
                //if we fail to return the SqlCommand, we need to close the connection ourselves
                cn.Close();
                throw;
            }
        }

        public static SqlCommand ExecuteSqlCommand(string connectionString, string CmdText)
        {
            //create & open a SqlConnection
            SqlConnection cn = new SqlConnection(connectionString);
            cn.Open();

            try
            {
                return new SqlCommand(CmdText, cn);
            }
            catch
            {
                //if we fail to return the SqlCommand, we need to close the connection ourselves
                cn.Close();
                throw;
            }
        }

        #endregion
    }

}

ListBaseDataSet.cs实例如下：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Data;
using QuestionsDbSLModel;

namespace QuestionsDbSL.Web.ClientBin
{
    /// <summary>
    /// 用于进行通用数据转化的类
    /// 将数据库中取出的数据通过 webserice传到SL端
    /// </summary>
    public class ListBaseDataSet
    {
        /// <summary>
        /// 按列的次序，将值依次转换到ListBaseVar中
        /// 按记录条数，将记录压到列表中
        /// </summary>
        /// <param name="p_DataSet"></param>
        /// <param name="p_TableIndex"></param>
        /// <returns></returns>
        public static List<BaseVars> DataSetToListBaseVars(DataSet p_DataSet, int p_TableIndex)
        {
            if (p_DataSet == null || p_DataSet.Tables.Count < 0)
                return null;
            if (p_TableIndex > p_DataSet.Tables.Count - 1)
                return null;
            if (p_TableIndex < 0)
                p_TableIndex = 0;

            DataTable p_Data = p_DataSet.Tables[p_TableIndex];
            List<BaseVars> result = new List<BaseVars>();
            lock (p_Data)
            {   
                for (int j = 0; j < p_Data.Rows.Count; j++)
                {
                    BaseVars lbv = new BaseVars();
                    for (int k = 0; k < p_Data.Columns.Count; k++)
                    {
                        if (p_Data.Rows[j][k].GetType() == typeof(string))
                        {
                            lbv.ListString.Add(p_Data.Rows[j][k].ToString());
                        }
                        else if (p_Data.Rows[j][k].GetType() == typeof(int))
                        {
                            lbv.ListInt.Add((int)(p_Data.Rows[j][k]));
                        }
                        else if (p_Data.Rows[j][k].GetType() == typeof(bool))
                        {
                            lbv.ListBool.Add((bool)(p_Data.Rows[j][k]));
                        }
                        else if (p_Data.Rows[j][k].GetType() == typeof(byte))
                        {
                            lbv.ListByte.Add((byte)(p_Data.Rows[j][k]));
                        }
                        else if (p_Data.Rows[j][k].GetType() == typeof(float))
                        {
                            lbv.ListFloat.Add((float)(p_Data.Rows[j][k]));
                        }
                        else if (p_Data.Rows[j][k].GetType() == typeof(double))
                        {
                            lbv.ListDouble.Add((double)(p_Data.Rows[j][k]));
                        }
                    }

                    result.Add(lbv);
                }
            }
            return result;
        }
    }
}