.net 开发框架（一）[数据通用层]

　　做开发也有不少年月了，刚入行时，只知道不断重复着写SqlConnection啊，SqlCommand啊等等方法啊，写多了实在感到很枯燥，那么为何不把它们封装起来，做成通用的呢？于是琢磨着开始把常用的方法封装成类库，目的只有一个：实现基本的数据层通用，不用为移植数据库而修改太多的数据层代码，不用在项目中重复写那些简单的数据操作方法，提高项目的开发速度。于是DevNet类库形成。

　　自DevNet类库形成后，一直在项目中使用，最近在思索如何再次增强其功能，让她适用的范围更广，苦于经验、思路有限，一直没有找到更好的方法，故将DevNet在此详细描述，还请高手们多提宝贵建议。

　　发现文字表达能力非常的差，悲哀啊！还是闲话少说，直接说该类库。

　　首先声明：该类库中的方法借鉴了网络上很多好的思路，在此表示非常感谢！因为借鉴的地方很多，现在也无法一一罗列，如发现该类库中使用了您的思路，还请多多包涵！

　　要想做成通用的开发类库，适用多数据库，类似于DBHelper的类也是必不可少，只不过我做成了抽象类，DBAccessBase.cs,以下是部分代码

    /// <summary>
    /// 通用数据库访问基类
    /// </summary>

    //[LicenseProvider(typeof(DevNetLicenseProvider))]  //License，类库中已注释
     public class DBAccessBase
    {
        /// <summary>
        /// 静态的 DataTable ExtendedProperties 属性
        /// </summary>
        internal static string C_PROP_SQL = "SourceSQL";
        /// <summary>
        /// 连接对象
        /// </summary>
        protected DbConnection con;
        /// <summary>
        /// 事务对象
        /// </summary>
        protected DbTransaction trans;

        /// <summary>
        /// 构造函数
        /// </summary>
        public DBAccessBase()
        {
           // DevNetLicenseProvider.ValidateLicense(typeof (DBConnect), this);
        }

        /// <summary>
        /// 构造函数
        /// </summary>
        /// <param name="dbConnection">DbConnection</param>
        public DBAccessBase(DbConnection dbConnection):this()
        {
            this.con = dbConnection;
        }

        /// <summary>
        /// 析构函数
        /// </summary>
        ~DBAccessBase()
        {
            con = null;
            trans = null;
        }

        /// <summary>
        /// 打开连接
        /// </summary>
        public virtual void Open()
        {
            if (con != null)
            {
                if (con.State == ConnectionState.Broken)
                    this.con.Close();
                if(con.State == ConnectionState.Closed)
                    this.con.Open();
            }
        }

        /// <summary>
        /// 关闭连接
        /// </summary>
        public virtual void Close()
        {
            if (con != null && con.State != ConnectionState.Closed)
                this.con.Close();
        }

        /// <summary>
        /// 开始事务
        /// </summary>
        public virtual void BeginTransaction()
        {
            if (con == null || con.State == ConnectionState.Closed)
                throw new Exception("Connection is Null or Not Open");

            this.trans = this.con.BeginTransaction();
        }

        /// <summary>
        /// 开始事务
        /// </summary>
        /// <param name="isoLationLevel">事务锁定行为</param>
        public virtual void BeginTransaction(IsolationLevel isoLationLevel)
        {
            if (con == null || con.State == ConnectionState.Closed)
                throw new Exception("Connection is Null or Not Open");
           this.trans = this.con.BeginTransaction(isoLationLevel);
        }

        /// <summary>
        /// 回滚事务
        /// </summary>
        public virtual void RollBackTransaction()
        {
            if (this.trans == null)
                throw new Exception("Transaction Not Begin");

            this.trans.Rollback();
            this.trans.Dispose();
            this.trans = null;
        }

        /// <summary>
        /// 提交事务
        /// </summary>
        public virtual void CommitTransaction()
        {
            if (this.trans == null)
                throw new Exception("Transaction Not Begin");

            this.trans.Commit();
            this.trans.Dispose();
            this.trans = null;
        }

         /// <summary>
        /// 创建参数
        /// </summary>
        /// <param name="cmd"></param>
        /// <param name="parameterName"></param>
        /// <param name="direction"></param>
        /// <param name="paraType"></param>
        /// <param name="size"></param>
        /// <returns></returns>
        public DbParameter CreateCmdParameter(DbCommand cmd, string parameterName, ParameterDirection direction, DbType paraType, int size)
        {
            DbParameter parameter = cmd.CreateParameter();
            parameter.ParameterName = parameterName;
            parameter.Direction = direction;
            if (this.con is OleDbConnection && (paraType == DbType.DateTime))
            {
                ((OleDbParameter)parameter).OleDbType = OleDbType.Date;
            }
            else
                parameter.DbType = paraType;
            parameter.Size = size;
            return parameter;
        }

         /// <summary>
        /// 创建参数
        /// </summary>
        /// <param name="cmd"></param>
        /// <param name="parameterName"></param>
        /// <param name="direction"></param>
        /// <param name="paraType"></param>
        /// <param name="size"></param>
        /// <param name="Value"></param>
        /// <returns></returns>
        public DbParameter CreateCmdParameter(DbCommand cmd, string parameterName, ParameterDirection direction, DbType paraType, int size, object Value)
        {
            DbParameter parameter = this.CreateCmdParameter(cmd, parameterName, direction, paraType, size);
            parameter.Value = Value;
            return parameter;
        }

        /// <summary>
        /// 增加一个参数
        /// </summary>
        /// <param name="cmd"></param>
        /// <param name="paramName"></param>
        /// <param name="paramValue"></param>
        public virtual void AddCmdParamWithValue(DbCommand cmd, string paramName, object paramValue)
        {
            if (cmd is SqlCommand)
                ((SqlCommand)cmd).Parameters.AddWithValue(paramName, paramValue);
            else if (cmd is OleDbCommand)
                ((OleDbCommand)cmd).Parameters.AddWithValue(paramName, paramValue);
            else if (cmd is System.Data.OracleClient.OracleCommand)
                ((System.Data.OracleClient.OracleCommand)cmd).Parameters.AddWithValue(paramName, paramValue);
          else if (cmd is MySqlDBAccess.MySqlCommand)
                ((MySqlDBAccess.MySqlCommand)cmd).Parameters.AddWithValue(paramName, paramValue);
          else
                throw new Exception("DbCommand Error!");
        }

         /// <summary>
        /// 创建 DbCommandBuilder
        /// </summary>
        /// <param name="da"></param>
        /// <returns></returns>
        public virtual DbCommandBuilder CreateCommandBuilder(DbDataAdapter da)
        {
            if (da is SqlDataAdapter)
                return new SqlCommandBuilder((SqlDataAdapter)da);
            else if (da is OleDbDataAdapter)
                return new OleDbCommandBuilder((OleDbDataAdapter)da);
            else if (da is System.Data.OracleClient.OracleDataAdapter)
                return new System.Data.OracleClient.OracleCommandBuilder((System.Data.OracleClient.OracleDataAdapter)da);
            else if (da is MySqlDBAccess.MySqlDataAdapter)
                return new MySqlDBAccess.MySqlCommandBuilder((MySqlDBAccess.MySqlDataAdapter)da);
            return null;
        }
           /// <summary>
        /// 创建 DbDataAdapter
        /// </summary>
        /// <param name="selectCmd">DbCommand</param>
        /// <returns></returns>
        public virtual DbDataAdapter CreateDbAdapter(DbCommand selectCmd)
        {
            if (selectCmd is SqlCommand)
                return new SqlDataAdapter((SqlCommand)selectCmd);
            else if (selectCmd is OleDbCommand)
                return new OleDbDataAdapter((OleDbCommand)selectCmd);
            else if (selectCmd is System.Data.OracleClient.OracleCommand)
                return new System.Data.OracleClient.OracleDataAdapter((System.Data.OracleClient.OracleCommand)selectCmd);
            else if (selectCmd is MySqlDBAccess.MySqlCommand)
                return new MySqlDBAccess.MySqlDataAdapter((MySqlDBAccess.MySqlCommand)selectCmd);
             return null;
        }

         /// <summary>
        /// 创建DbDataAdapter
        /// </summary>
        /// <param name="selectCmd"></param>
        /// <returns></returns>
        public DbDataAdapter CreateDbAdapter(string selectCmd)
        {
            DbCommand dbCmd = this.PrepareCommand(CommandType.Text, selectCmd, null);
           
            return this.CreateDbAdapter(dbCmd);
           
        }
         /// <summary>
        /// 执行DbCommand
        /// </summary>
        /// <param name="selectCommand"></param>
        /// <returns></returns>
        public DataTable ExecuteDataTable(DbCommand selectCommand)
        {
            return this.ExecuteDataTable(selectCommand, null);
        }

        /// <summary>
        /// 获取一个DataTable
        /// </summary>
        /// <param name="commandText"></param>
        /// <returns></returns>
        public DataTable ExecuteDataTable(string commandText)
        {
            return this.ExecuteDataTable(CommandType.Text, commandText, null);
        }

        /// <summary>
        /// 获取一个DataTable
        /// </summary>
        /// <param name="selectCommand"></param>
        /// <param name="srcTable"></param>
        /// <returns></returns>
        public virtual DataTable ExecuteDataTable(DbCommand selectCommand, string srcTable)
        {
            DataTable dataTable = new DataTable();
            using (DbDataAdapter adapter = this.CreateDbAdapter(selectCommand))
            {
                adapter.Fill(dataTable);
                dataTable.ExtendedProperties[C_PROP_SQL] = selectCommand.CommandText;
                if (!String.IsNullOrEmpty(srcTable))
                {
                    dataTable.TableName = srcTable;
                }
            }
            return dataTable;
        }

        /// <summary>
        /// 获取一个DataTable
        /// </summary>
        /// <param name="commandText"></param>
        /// <param name="srcTable"></param>
        /// <returns></returns>
        public DataTable ExecuteDataTable(string commandText, string srcTable)
        {
            DataTable table = this.ExecuteDataTable(CommandType.Text, commandText, null);
            if(!String.IsNullOrEmpty(srcTable))
                table.TableName = srcTable;
            return table;
        }

        /// <summary>
        /// 获取指定记录数集合的表
        /// </summary>
        /// <param name="commandText"></param>
        /// <param name="startIndex"></param>
        /// <param name="maxRecords"></param>
        /// <returns></returns>
        public DataTable ExecuteDataTable(string commandText, int startIndex, int maxRecords)
        {
            DataTable dt;// = new DataTable();
            using (DbCommand cmd = this.PrepareCommand(CommandType.Text, commandText, null))
            {
                dt = ExecuteDataTable(cmd, startIndex, maxRecords);
            }
            return dt;
        }

        /// <summary>
        /// 获取指定记录数集合的表
        /// </summary>
        /// <param name="selectCmd"></param>
        /// <param name="startIndex"></param>
        /// <param name="maxRecords"></param>
        /// <returns></returns>
        public virtual DataTable ExecuteDataTable(DbCommand selectCmd, int startIndex, int maxRecords)
        {
            DataTable dt = new DataTable();
            using (DbDataAdapter da = this.CreateDbAdapter(selectCmd))
            {
                da.Fill(startIndex, maxRecords, dt);
                dt.ExtendedProperties[C_PROP_SQL] = selectCmd.CommandText;
            }
            return dt;
        }

        /// <summary>
        /// 获取一个DataTable
        /// </summary>
        /// <param name="cmdType"></param>
        /// <param name="cmdText"></param>
        /// <param name="commandParameters"></param>
        /// <returns></returns>
        public virtual DataTable ExecuteDataTable(CommandType cmdType, string cmdText, params DbParameter[] commandParameters)
        {
            DataTable dataTable = new DataTable();
            using(DbCommand selectCommand = this.PrepareCommand(cmdType, cmdText, commandParameters))
            {
                using (DbDataAdapter adapter = this.CreateDbAdapter(selectCommand))
                {
                    adapter.Fill(dataTable);
                    dataTable.ExtendedProperties[C_PROP_SQL] = cmdText;
                }
                selectCommand.Parameters.Clear();
            }
            return dataTable;
        }

        /// <summary>
        /// 执行ExecuteNonQuery
        /// </summary>
        /// <param name="cmdText"></param>
        /// <returns></returns>
        public int ExecuteNonQuery(string cmdText)
        {
            return this.ExecuteNonQuery(CommandType.Text, cmdText, null);
        }

        /// <summary>
        /// 执行ExecuteNonQuery
        /// </summary>
        /// <param name="cmdType"></param>
        /// <param name="cmdText"></param>
        /// <param name="commandParameters"></param>
        /// <returns></returns>
        public int ExecuteNonQuery(CommandType cmdType, string cmdText, params DbParameter[] commandParameters)
        {
            using (DbCommand dbCmd = this.PrepareCommand(cmdType, cmdText, commandParameters))
            {
                int i = dbCmd.ExecuteNonQuery();
                dbCmd.Parameters.Clear();
                return i;
            }
        }

        /// <summary>
        /// 获取DbDataReader
        /// </summary>
        /// <param name="cmdText"></param>
        /// <returns></returns>
        public DbDataReader ExecuteReader(string cmdText)
        {
            return this.ExecuteReader(CommandType.Text, cmdText, null);
        }

        /// <summary>
        /// 获取DbDataReader
        /// </summary>
        /// <param name="cmdType"></param>
        /// <param name="cmdText"></param>
        /// <param name="commandParameters"></param>
        /// <returns></returns>
        public DbDataReader ExecuteReader(CommandType cmdType, string cmdText, params DbParameter[] commandParameters)
        {
            return this.ExecuteReader(cmdType, cmdText, CommandBehavior.CloseConnection, commandParameters);
        }

        /// <summary>
        /// 获取DbDataReader
        /// </summary>
        /// <param name="cmdType"></param>
        /// <param name="cmdText"></param>
        /// <param name="cmdBehavior"></param>
        /// <param name="commandParameters"></param>
        /// <returns></returns>
        public DbDataReader ExecuteReader(CommandType cmdType, string cmdText,CommandBehavior cmdBehavior, params DbParameter[] commandParameters)
        {
            DbCommand dbCmd = this.PrepareCommand(cmdType, cmdText, commandParameters);

            DbDataReader read = dbCmd.ExecuteReader(cmdBehavior);
            dbCmd.Parameters.Clear();
            return read;
        }

        /// <summary>
        /// 获取ExecuteScalar
        /// </summary>
        /// <param name="cmdText"></param>
        /// <returns></returns>
        public object ExecuteScalar(string cmdText)
        {
            return this.ExecuteScalar(CommandType.Text, cmdText, null);
        }

        /// <summary>
        /// 获取ExecuteScalar
        /// </summary>
        /// <param name="cmdType"></param>
        /// <param name="cmdText"></param>
        /// <param name="commandParameters"></param>
        /// <returns></returns>
        public object ExecuteScalar(CommandType cmdType, string cmdText, params DbParameter[] commandParameters)
        {
            using (DbCommand dbCmd = this.PrepareCommand(cmdType, cmdText, commandParameters))
            {
                object obj = dbCmd.ExecuteScalar();
                dbCmd.Parameters.Clear();
                return obj;
            }
        }

        /// <summary>
        /// 创建DbCommand
        /// </summary>
        /// <returns></returns>
        public virtual DbCommand CreateCommand()
        {
            DbCommand cmd = this.con.CreateCommand();
            if (this.trans != null)
                cmd.Transaction = this.trans;
            return cmd;
        }

        /// <summary>
        /// 创建DbCommand
        /// </summary>
        /// <returns></returns>
        public virtual DbCommand CreateCommand(string commandText)
        {
            DbCommand command = this.CreateCommand();
            command.CommandText = commandText;
            return command;
        }

        /// <summary>
        ///
        /// </summary>
        /// <param name="cmdType"></param>
        /// <param name="cmdText"></param>
        /// <param name="cmdParms"></param>
        /// <returns></returns>
        protected virtual DbCommand PrepareCommand(CommandType cmdType, string cmdText, params DbParameter[] cmdParms)
        {
            DbCommand command = this.CreateCommand(cmdText);
             command.CommandType = cmdType;

            if (cmdParms != null)
            {
                foreach (DbParameter parameter in cmdParms)
                {
                    command.Parameters.Add(parameter);
                }
            }
            return command;
        }

        /// <summary>
        /// 更新DataTable
        /// </summary>
        /// <param name="dataTable"></param>
        /// <returns></returns>
        public int UpdateDataTable(DataTable dataTable)
        {
            return this.UpdateDataTable(dataTable, dataTable.TableName);
        }

        /// <summary>
        /// 更新DataTable
        /// </summary>
        /// <param name="dataTable"></param>
        /// <param name="srcTable"></param>
        /// <returns></returns>
        public virtual int UpdateDataTable(DataTable dataTable, string srcTable)
        {
            string cmdText = null;
            if (dataTable.ExtendedProperties.Contains(C_PROP_SQL))
            {
                cmdText = dataTable.ExtendedProperties[C_PROP_SQL].ToString();
                if (cmdText.IndexOf("select", StringComparison.OrdinalIgnoreCase) >= 0 && cmdText.IndexOf("from", StringComparison.OrdinalIgnoreCase) >= 0)
                {
                    int index = cmdText.IndexOf(" where ", StringComparison.OrdinalIgnoreCase);
                    if (index > 0)
                    {
                        cmdText = cmdText.Substring(0, index);
                    }
                    goto Flag;
                }
            }

            if (String.IsNullOrEmpty(srcTable) && String.IsNullOrEmpty(dataTable.TableName))
            {
                throw new Exception("没有设置TableName，或DataTable不是由DBConnect创建");
            }
            if (String.IsNullOrEmpty(srcTable))
                srcTable = dataTable.TableName;

            System.Text.StringBuilder builder = new System.Text.StringBuilder();
            foreach (DataColumn column in dataTable.Columns)
            {
                builder.Append(",[");
                builder.Append(column.ColumnName);
                builder.Append("]");
            }
            builder.Append(" From ");
            builder.Append(srcTable);
            cmdText = "Select " + builder.ToString(1, builder.Length - 1);

            Flag:
           
            using (DbDataAdapter da = this.CreateDbAdapter(this.PrepareCommand(CommandType.Text, cmdText, null)))
            {
                if (da != null)
                {
                    this.CreateCommandBuilder(da);
                    return da.Update(dataTable);
                }
            }
            return -1;
        }

         /// <summary>
        /// Return ConnectionState
        /// </summary>
        public virtual ConnectionState State
        {
            get{ return this.con.State; }
        }

        /// <summary>
        /// Return or Set Connection's Trans
        /// </summary>
        public virtual DbTransaction Transaction
        {
            get { return this.trans; }
            set { this.trans = value; }
        }

        /// <summary>
        /// Return or Set DbConnection
        /// </summary>
        public virtual DbConnection DbConnection
        {
            get { return this.con; }
            set { this.con = value; }
        }

        /// <summary>
        /// 返回或设置连接的字符串
        /// </summary>
        public virtual string ConnectionString
        {
            get
            {
                if (con == null)
                    return string.Empty;
                return this.con.ConnectionString;
            }
            set
            {
                if (this.con != null)
                    this.con.ConnectionString = value;
            }
        }

  }

这个是该类库最底层的数据操作类了， 我想大家看了就明白了！

我把该类作为基类派生出SqlDbDirect.cs、OleDbDirect.cs、OracleDbDirect.cs和MySqlDbDirect.cs目前支持这几种数据库，数据库类型枚举：

    /// <summary>
    /// 数据库类型枚举
    /// </summary>
    public enum DBTypeEnum
    {
        /// <summary>
        /// Sql DataBase  1
        /// </summary>
        SQL = 1,
        /// <summary>
        /// OleDb Access DataBase  2
        /// </summary>
        OleDb = 2,
        /// <summary>
        /// Oracle DataBase  3
        /// </summary>
        Oracle = 3,
        /// <summary>
        /// ADO Access DataBase 4
        /// </summary>
        ADO = 4,
        /// <summary>
        /// MySql DataBase  5
        /// </summary>
        MySql = 5
    }　　

在以上基础上我封装了DBConnect.cs类，有兴趣的朋友可以查看帮助文档，该类进一步封装数据操作方法，增加编写代码的实用性和易操作性。贴上构造函数代码：

　　　static readonly string Provider = ConfigurationManager.AppSettings["Provider"];

        private DBAccessBase con = null;

       /// <summary>
        ///  构造函数 
        ///  配置文件    
        ///  (appSettings)
        ///  add key="Provider" value="sql"  (Sql,OleDb,Oracle,mysql )   
        ///  add key="sql" value="Data Source=.;Initial Catalog=test;Persist Security Info=True;User ID=sa;Password=sa"   
        ///  add key="oledb" value="Provider=Microsoft.Jet.OLEDB.4.0;Data Source=D:\sqldatabase\test.mdb"    
        ///  (appSettings)
        ///  无参数构造函数将自动创建连接
        /// </summary>
        public DBConnect()
        {
            if (String.IsNullOrEmpty(Provider))
            {
                   return;
            }

            string conStr = GetConStr();  //根据配置文件获取连接字符串
            if (!string.IsNullOrEmpty(conStr))
            {
                this.dbEnum = getDBEnum();  //获取数据库类型枚举
                setConnect(conStr);
            }
      }

　　　/// <summary>
        /// 构造函数
         /// </summary>
        /// <param name="dataBaseEnum">数据库类型枚举</param>
        /// <param name="connString">数据库的连接字符串</param>
        public DBConnect(DBTypeEnum dataBaseEnum, string connString)
        {
            this.dbEnum = dataBaseEnum;
            setConnect(connString);
        }

        void setConnect(string connString)
        {
            con = DBFactory.GetDBConnection(this.dbEnum, connString);  //使用工厂统一获取数据库连接对象
            ConnectString = connString;
        }

配置文件如下设置 ：

　　<appSettings>
    　　  <add key="Provider" value="sql" />
     　　 <add key="sql" value="Data Source=.;Initial Catalog=userinfo;Persist Security Info=True;User ID=sa;Password=sql" />
    </appSettings>

 至此，数据底层通用的代码编写完毕，还请大家多提建议，下一篇描述ScriptQuery.cs和实体层！

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