C# ORM框架

SQLSUGAR

http://www.codeisbug.com/Doc/8/1159

附带mysql工具类，最优使用上面sqlsugar

using System;
using System.Collections;
using System.Collections.Specialized;
using System.Data;
using MySql.Data.MySqlClient;
using System.Configuration;
using System.Data.Common;
using System.Collections.Generic;
using System.Data.SqlClient;
using System.Text;

namespace  PluginManager.PluginManagerCore
{
    /// <summary>  
    /// 数据访问抽象基础类  
    /// </summary>  
    public abstract class DbHelperMySQL
    {
        //数据库连接字符串(web.config来配置)，可以动态更改connectionString支持多数据库.       
        public static string connectionString = "Server=172.18.131.52;Database=zabbix; User=root;Password=123456;Use Procedure Bodies=false;Charset=utf8;Allow Zero Datetime=True; Pooling=True; Max Pool Size=50;";
        public DbHelperMySQL()
        {
        }
        public enum EffentNextType
        {
            /// <summary>
                    /// 对其他语句无任何影响 
                    /// </summary>
            None,
            /// <summary>
                    /// 当前语句必须为"select count(1) from .."格式，如果存在则继续执行，不存在回滚事务
                    /// </summary>
            WhenHaveContine,
            /// <summary>
                    /// 当前语句必须为"select count(1) from .."格式，如果不存在则继续执行，存在回滚事务
                    /// </summary>
            WhenNoHaveContine,
            /// <summary>
                    /// 当前语句影响到的行数必须大于0，否则回滚事务
                    /// </summary>
            ExcuteEffectRows,
            /// <summary>
                    /// 引发事件-当前语句必须为"select count(1) from .."格式，如果不存在则继续执行，存在回滚事务
                    /// </summary>
            SolicitationEvent
        }
        public class CommandInfo
        {
            public object ShareObject = null;
            public object OriginalData = null;
            event EventHandler _solicitationEvent;
            public event EventHandler SolicitationEvent
            {
                add
                {
                    _solicitationEvent += value;
                }
                remove
                {
                    _solicitationEvent -= value;
                }
            }
            public void OnSolicitationEvent()
            {
                if (_solicitationEvent != null)
                {
                    _solicitationEvent(this, new EventArgs());
                }
            }
            public string CommandText;
            public System.Data.Common.DbParameter[] Parameters;
            public EffentNextType EffentNextType = EffentNextType.None;
            public CommandInfo()
            {

            }
            public CommandInfo(string sqlText, SqlParameter[] para)
            {
                this.CommandText = sqlText;
                this.Parameters = para;
            }
            public CommandInfo(string sqlText, SqlParameter[] para, EffentNextType type)
            {
                this.CommandText = sqlText;
                this.Parameters = para;
                this.EffentNextType = type;
            }
        }

        /// <summary>  
        /// 得到最大值  
        /// </summary>  
        /// <param name="FieldName"></param>  
        /// <param name="TableName"></param>  
        /// <returns></returns>  
        public static int GetMaxID(string FieldName, string TableName)
        {
            string strsql = "select max(" + FieldName + ")+1 from " + TableName;
            object obj = GetSingle(strsql);
            if (obj == null)
            {
                return 1;
            }
            else
            {
                return int.Parse(obj.ToString());
            }
        }
        /// <summary>  
        /// 是否存在  
        /// </summary>  
        /// <param name="strSql"></param>  
        /// <returns></returns>  
        public static bool Exists(string strSql)
        {
            object obj = GetSingle(strSql);
            int cmdresult;
            if ((Object.Equals(obj, null)) || (Object.Equals(obj, System.DBNull.Value)))
            {
                cmdresult = 0;
            }
            else
            {
                cmdresult = int.Parse(obj.ToString());
            }
            if (cmdresult == 0)
            {
                return false;
            }
            else
            {
                return true;
            }
        }
        /// <summary>  
        /// 是否存在（基于MySqlParameter）  
        /// </summary>  
        /// <param name="strSql"></param>  
        /// <param name="cmdParms"></param>  
        /// <returns></returns>  
        public static bool Exists(string strSql, params MySqlParameter[] cmdParms)
        {
            object obj = GetSingle(strSql, cmdParms);
            int cmdresult;
            if ((Object.Equals(obj, null)) || (Object.Equals(obj, System.DBNull.Value)))
            {
                cmdresult = 0;
            }
            else
            {
                cmdresult = int.Parse(obj.ToString());
            }
            if (cmdresult == 0)
            {
                return false;
            }
            else
            {
                return true;
            }
        }


        /// <summary>  
        /// 执行SQL语句，返回影响的记录数  
        /// </summary>  
        /// <param name="SQLString">SQL语句</param>  
        /// <returns>影响的记录数</returns>  
        public static int ExecuteSql(string SQLString)
        {
            using (MySqlConnection connection = new MySqlConnection(connectionString))
            {
                using (MySqlCommand cmd = new MySqlCommand(SQLString, connection))
                {
                    try
                    {
                        connection.Open();
                        int rows = cmd.ExecuteNonQuery();
                        return rows;
                    }
                    catch (MySql.Data.MySqlClient.MySqlException e)
                    {
                        connection.Close();
                        throw e;
                    }
                }
            }
        }

        public static int ExecuteSqlByTime(string SQLString, int Times)
        {
            using (MySqlConnection connection = new MySqlConnection(connectionString))
            {
                using (MySqlCommand cmd = new MySqlCommand(SQLString, connection))
                {
                    try
                    {
                        connection.Open();
                        cmd.CommandTimeout = Times;
                        int rows = cmd.ExecuteNonQuery();
                        return rows;
                    }
                    catch (MySql.Data.MySqlClient.MySqlException e)
                    {
                        connection.Close();
                        throw e;
                    }
                }
            }
        }

        /// <summary>  
        /// 执行MySql和Oracle滴混合事务  
        /// </summary>  
        /// <param name="list">SQL命令行列表</param>  
        /// <param name="oracleCmdSqlList">Oracle命令行列表</param>  
        /// <returns>执行结果 0-由于SQL造成事务失败 -1 由于Oracle造成事务失败 1-整体事务执行成功</returns>  
        //public static int ExecuteSqlTran(List<CommandInfo> list, List<CommandInfo> oracleCmdSqlList)
        //{
        //    using (MySqlConnection conn = new MySqlConnection(connectionString))
        //    {
        //        conn.Open();
        //        MySqlCommand cmd = new MySqlCommand();
        //        cmd.Connection = conn;
        //        MySqlTransaction tx = conn.BeginTransaction();
        //        cmd.Transaction = tx;
        //        try
        //        {
        //            foreach (CommandInfo myDE in list)
        //            {
        //                string cmdText = myDE.CommandText;
        //                MySqlParameter[] cmdParms = (MySqlParameter[])myDE.Parameters;
        //                PrepareCommand(cmd, conn, tx, cmdText, cmdParms);
        //                if (myDE.EffentNextType == EffentNextType.SolicitationEvent)
        //                {
        //                    if (myDE.CommandText.ToLower().IndexOf("count(") == -1)
        //                    {
        //                        tx.Rollback();
        //                        throw new Exception("违背要求" + myDE.CommandText + "必须符合select count(..的格式");
        //                        //return 0;  
        //                    }

        //                    object obj = cmd.ExecuteScalar();
        //                    bool isHave = false;
        //                    if (obj == null && obj == DBNull.Value)
        //                    {
        //                        isHave = false;
        //                    }
        //                    isHave = Convert.ToInt32(obj) > 0;
        //                    if (isHave)
        //                    {
        //                        //引发事件  
        //                        myDE.OnSolicitationEvent();
        //                    }
        //                }
        //                if (myDE.EffentNextType == EffentNextType.WhenHaveContine || myDE.EffentNextType == EffentNextType.WhenNoHaveContine)
        //                {
        //                    if (myDE.CommandText.ToLower().IndexOf("count(") == -1)
        //                    {
        //                        tx.Rollback();
        //                        throw new Exception("SQL:违背要求" + myDE.CommandText + "必须符合select count(..的格式");
        //                        //return 0;  
        //                    }

        //                    object obj = cmd.ExecuteScalar();
        //                    bool isHave = false;
        //                    if (obj == null && obj == DBNull.Value)
        //                    {
        //                        isHave = false;
        //                    }
        //                    isHave = Convert.ToInt32(obj) > 0;

        //                    if (myDE.EffentNextType == EffentNextType.WhenHaveContine && !isHave)
        //                    {
        //                        tx.Rollback();
        //                        throw new Exception("SQL:违背要求" + myDE.CommandText + "返回值必须大于0");
        //                        //return 0;  
        //                    }
        //                    if (myDE.EffentNextType == EffentNextType.WhenNoHaveContine && isHave)
        //                    {
        //                        tx.Rollback();
        //                        throw new Exception("SQL:违背要求" + myDE.CommandText + "返回值必须等于0");
        //                        //return 0;  
        //                    }
        //                    continue;
        //                }
        //                int val = cmd.ExecuteNonQuery();
        //                if (myDE.EffentNextType == EffentNextType.ExcuteEffectRows && val == 0)
        //                {
        //                    tx.Rollback();
        //                    throw new Exception("SQL:违背要求" + myDE.CommandText + "必须有影响行");
        //                    //return 0;  
        //                }
        //                cmd.Parameters.Clear();
        //            }
        //            string oraConnectionString = PubConstant.GetConnectionString("ConnectionStringPPC");
        //            bool res = OracleHelper.ExecuteSqlTran(oraConnectionString, oracleCmdSqlList);
        //            if (!res)
        //            {
        //                tx.Rollback();
        //                throw new Exception("执行失败");
        //                // return -1;  
        //            }
        //            tx.Commit();
        //            return 1;
        //        }
        //        catch (MySql.Data.MySqlClient.MySqlException e)
        //        {
        //            tx.Rollback();
        //            throw e;
        //        }
        //        catch (Exception e)
        //        {
        //            tx.Rollback();
        //            throw e;
        //        }
        //    }
        //}
        /// <summary>  
        /// 执行多条SQL语句，实现数据库事务。  
        /// </summary>  
        /// <param name="SQLStringList">多条SQL语句</param>       
        public static int ExecuteSqlTran(List<String> SQLStringList)
        {
            using (MySqlConnection conn = new MySqlConnection(connectionString))
            {
                conn.Open();
                MySqlCommand cmd = new MySqlCommand();
                cmd.Connection = conn;
                MySqlTransaction tx = conn.BeginTransaction();
                cmd.Transaction = tx;
                try
                {
                    int count = 0;
                    for (int n = 0; n < SQLStringList.Count; n++)
                    {
                        string strsql = SQLStringList[n];
                        if (strsql.Trim().Length > 1)
                        {
                            cmd.CommandText = strsql;
                            count += cmd.ExecuteNonQuery();
                        }
                    }
                    tx.Commit();
                    return count;
                }
                catch
                {
                    tx.Rollback();
                    return 0;
                }
            }
        }
        /// <summary>  
        /// 执行带一个存储过程参数的的SQL语句。  
        /// </summary>  
        /// <param name="SQLString">SQL语句</param>  
        /// <param name="content">参数内容,比如一个字段是格式复杂的文章，有特殊符号，可以通过这个方式添加</param>  
        /// <returns>影响的记录数</returns>  
        public static int ExecuteSql(string SQLString, string content)
        {
            using (MySqlConnection connection = new MySqlConnection(connectionString))
            {
                MySqlCommand cmd = new MySqlCommand(SQLString, connection);
                MySql.Data.MySqlClient.MySqlParameter myParameter = new MySql.Data.MySqlClient.MySqlParameter("@content", SqlDbType.NText);
                myParameter.Value = content;
                cmd.Parameters.Add(myParameter);
                try
                {
                    connection.Open();
                    int rows = cmd.ExecuteNonQuery();
                    return rows;
                }
                catch (MySql.Data.MySqlClient.MySqlException e)
                {
                    throw e;
                }
                finally
                {
                    cmd.Dispose();
                    connection.Close();
                }
            }
        }
        /// <summary>  
        /// 执行带一个存储过程参数的的SQL语句。  
        /// </summary>  
        /// <param name="SQLString">SQL语句</param>  
        /// <param name="content">参数内容,比如一个字段是格式复杂的文章，有特殊符号，可以通过这个方式添加</param>  
        /// <returns>影响的记录数</returns>  
        public static object ExecuteSqlGet(string SQLString, string content)
        {
            using (MySqlConnection connection = new MySqlConnection(connectionString))
            {
                MySqlCommand cmd = new MySqlCommand(SQLString, connection);
                MySql.Data.MySqlClient.MySqlParameter myParameter = new MySql.Data.MySqlClient.MySqlParameter("@content", SqlDbType.NText);
                myParameter.Value = content;
                cmd.Parameters.Add(myParameter);
                try
                {
                    connection.Open();
                    object obj = cmd.ExecuteScalar();
                    if ((Object.Equals(obj, null)) || (Object.Equals(obj, System.DBNull.Value)))
                    {
                        return null;
                    }
                    else
                    {
                        return obj;
                    }
                }
                catch (MySql.Data.MySqlClient.MySqlException e)
                {
                    throw e;
                }
                finally
                {
                    cmd.Dispose();
                    connection.Close();
                }
            }
        }
        /// <summary>  
        /// 向数据库里插入图像格式的字段(和上面情况类似的另一种实例)  
        /// </summary>  
        /// <param name="strSQL">SQL语句</param>  
        /// <param name="fs">图像字节,数据库的字段类型为image的情况</param>  
        /// <returns>影响的记录数</returns>  
        public static int ExecuteSqlInsertImg(string strSQL, byte[] fs)
        {
            using (MySqlConnection connection = new MySqlConnection(connectionString))
            {
                MySqlCommand cmd = new MySqlCommand(strSQL, connection);
                MySql.Data.MySqlClient.MySqlParameter myParameter = new MySql.Data.MySqlClient.MySqlParameter("@fs", SqlDbType.Image);
                myParameter.Value = fs;
                cmd.Parameters.Add(myParameter);
                try
                {
                    connection.Open();
                    int rows = cmd.ExecuteNonQuery();
                    return rows;
                }
                catch (MySql.Data.MySqlClient.MySqlException e)
                {
                    throw e;
                }
                finally
                {
                    cmd.Dispose();
                    connection.Close();
                }
            }
        }

        /// <summary>  
        /// 执行一条计算查询结果语句，返回查询结果（object）。  
        /// </summary>  
        /// <param name="SQLString">计算查询结果语句</param>  
        /// <returns>查询结果（object）</returns>  
        public static object GetSingle(string SQLString)
        {
            using (MySqlConnection connection = new MySqlConnection(connectionString))
            {
                using (MySqlCommand cmd = new MySqlCommand(SQLString, connection))
                {
                    try
                    {
                        connection.Open();
                        object obj = cmd.ExecuteScalar();
                        if ((Object.Equals(obj, null)) || (Object.Equals(obj, System.DBNull.Value)))
                        {
                            return null;
                        }
                        else
                        {
                            return obj;
                        }
                    }
                    catch (MySql.Data.MySqlClient.MySqlException e)
                    {
                        connection.Close();
                        throw e;
                    }
                }
            }
        }
        public static object GetSingle(string SQLString, int Times)
        {
            using (MySqlConnection connection = new MySqlConnection(connectionString))
            {
                using (MySqlCommand cmd = new MySqlCommand(SQLString, connection))
                {
                    try
                    {
                        connection.Open();
                        cmd.CommandTimeout = Times;
                        object obj = cmd.ExecuteScalar();
                        if ((Object.Equals(obj, null)) || (Object.Equals(obj, System.DBNull.Value)))
                        {
                            return null;
                        }
                        else
                        {
                            return obj;
                        }
                    }
                    catch (MySql.Data.MySqlClient.MySqlException e)
                    {
                        connection.Close();
                        throw e;
                    }
                }
            }
        }
        /// <summary>  
        /// 执行查询语句，返回MySqlDataReader ( 注意：调用该方法后，一定要对MySqlDataReader进行Close )  
        /// </summary>  
        /// <param name="strSQL">查询语句</param>  
        /// <returns>MySqlDataReader</returns>  
        public static MySqlDataReader ExecuteReader(string strSQL)
        {
            MySqlConnection connection = new MySqlConnection(connectionString);
            MySqlCommand cmd = new MySqlCommand(strSQL, connection);
            try
            {
                connection.Open();
                MySqlDataReader myReader = cmd.ExecuteReader(CommandBehavior.CloseConnection);
                return myReader;
            }
            catch (MySql.Data.MySqlClient.MySqlException e)
            {
                throw e;
            }

        }
        /// <summary>  
        /// 执行查询语句，返回DataSet  
        /// </summary>  
        /// <param name="SQLString">查询语句</param>  
        /// <returns>DataSet</returns>  
        public static DataSet Query(string SQLString)
        {
            using (MySqlConnection connection = new MySqlConnection(connectionString))
            {
                DataSet ds = new DataSet();
                try
                {
                    connection.Open();
                    MySqlDataAdapter command = new MySqlDataAdapter(SQLString, connection);
                    command.Fill(ds, "dataset");
                }
                catch (MySql.Data.MySqlClient.MySqlException ex)
                {
                    throw new Exception(ex.Message);
                }
                return ds;
            }
        }
        public static DataSet Query(string SQLString, int Times)
        {
            using (MySqlConnection connection = new MySqlConnection(connectionString))
            {
                DataSet ds = new DataSet();
                try
                {
                    connection.Open();
                    MySqlDataAdapter command = new MySqlDataAdapter(SQLString, connection);
                    command.SelectCommand.CommandTimeout = Times;
                    command.Fill(ds, "ds");
                }
                catch (MySql.Data.MySqlClient.MySqlException ex)
                {
                    throw new Exception(ex.Message);
                }
                return ds;
            }
        }




        /// <summary>  
        /// 执行SQL语句，返回影响的记录数  
        /// </summary>  
        /// <param name="SQLString">SQL语句</param>  
        /// <returns>影响的记录数</returns>  
        public static int ExecuteSql(string SQLString, params MySqlParameter[] cmdParms)
        {
            using (MySqlConnection connection = new MySqlConnection(connectionString))
            {
                using (MySqlCommand cmd = new MySqlCommand())
                {
                    try
                    {
                        PrepareCommand(cmd, connection, null, SQLString, cmdParms);
                        int rows = cmd.ExecuteNonQuery();
                        cmd.Parameters.Clear();
                        return rows;
                    }
                    catch (MySql.Data.MySqlClient.MySqlException e)
                    {
                        throw e;
                    }
                }
            }
        }


        /// <summary>  
        /// 执行多条SQL语句，实现数据库事务。  
        /// </summary>  
        /// <param name="SQLStringList">SQL语句的哈希表（key为sql语句，value是该语句的MySqlParameter[]）</param>  
        public static void ExecuteSqlTran(Hashtable SQLStringList)
        {
            using (MySqlConnection conn = new MySqlConnection(connectionString))
            {
                conn.Open();
                using (MySqlTransaction trans = conn.BeginTransaction())
                {
                    MySqlCommand cmd = new MySqlCommand();
                    try
                    {
                        //循环  
                        foreach (DictionaryEntry myDE in SQLStringList)
                        {
                            string cmdText = myDE.Key.ToString();
                            MySqlParameter[] cmdParms = (MySqlParameter[])myDE.Value;
                            PrepareCommand(cmd, conn, trans, cmdText, cmdParms);
                            int val = cmd.ExecuteNonQuery();
                            cmd.Parameters.Clear();
                        }
                        trans.Commit();
                    }
                    catch
                    {
                        trans.Rollback();
                        throw;
                    }
                }
            }
        }
        /// <summary>  
        /// 执行多条SQL语句，实现数据库事务。  
        /// </summary>  
        /// <param name="SQLStringList">SQL语句的哈希表（key为sql语句，value是该语句的MySqlParameter[]）</param>  
        public static int ExecuteSqlTran(System.Collections.Generic.List<CommandInfo> cmdList)
        {
            using (MySqlConnection conn = new MySqlConnection(connectionString))
            {
                conn.Open();
                using (MySqlTransaction trans = conn.BeginTransaction())
                {
                    MySqlCommand cmd = new MySqlCommand();
                    try
                    {
                        int count = 0;
                        //循环  
                        foreach (CommandInfo myDE in cmdList)
                        {
                            string cmdText = myDE.CommandText;
                            MySqlParameter[] cmdParms = (MySqlParameter[])myDE.Parameters;
                            PrepareCommand(cmd, conn, trans, cmdText, cmdParms);

                            if (myDE.EffentNextType == EffentNextType.WhenHaveContine || myDE.EffentNextType == EffentNextType.WhenNoHaveContine)
                            {
                                if (myDE.CommandText.ToLower().IndexOf("count(") == -1)
                                {
                                    trans.Rollback();
                                    return 0;
                                }

                                object obj = cmd.ExecuteScalar();
                                bool isHave = false;
                                if (obj == null && obj == DBNull.Value)
                                {
                                    isHave = false;
                                }
                                isHave = Convert.ToInt32(obj) > 0;

                                if (myDE.EffentNextType == EffentNextType.WhenHaveContine && !isHave)
                                {
                                    trans.Rollback();
                                    return 0;
                                }
                                if (myDE.EffentNextType == EffentNextType.WhenNoHaveContine && isHave)
                                {
                                    trans.Rollback();
                                    return 0;
                                }
                                continue;
                            }
                            int val = cmd.ExecuteNonQuery();
                            count += val;
                            if (myDE.EffentNextType == EffentNextType.ExcuteEffectRows && val == 0)
                            {
                                trans.Rollback();
                                return 0;
                            }
                            cmd.Parameters.Clear();
                        }
                        trans.Commit();
                        return count;
                    }
                    catch
                    {
                        trans.Rollback();
                        throw;
                    }
                }
            }
        }
        /// <summary>  
        /// 执行多条SQL语句，实现数据库事务。  
        /// </summary>  
        /// <param name="SQLStringList">SQL语句的哈希表（key为sql语句，value是该语句的MySqlParameter[]）</param>  
        public static void ExecuteSqlTranWithIndentity(System.Collections.Generic.List<CommandInfo> SQLStringList)
        {
            using (MySqlConnection conn = new MySqlConnection(connectionString))
            {
                conn.Open();
                using (MySqlTransaction trans = conn.BeginTransaction())
                {
                    MySqlCommand cmd = new MySqlCommand();
                    try
                    {
                        int indentity = 0;
                        //循环  
                        foreach (CommandInfo myDE in SQLStringList)
                        {
                            string cmdText = myDE.CommandText;
                            MySqlParameter[] cmdParms = (MySqlParameter[])myDE.Parameters;
                            foreach (MySqlParameter q in cmdParms)
                            {
                                if (q.Direction == ParameterDirection.InputOutput)
                                {
                                    q.Value = indentity;
                                }
                            }
                            PrepareCommand(cmd, conn, trans, cmdText, cmdParms);
                            int val = cmd.ExecuteNonQuery();
                            foreach (MySqlParameter q in cmdParms)
                            {
                                if (q.Direction == ParameterDirection.Output)
                                {
                                    indentity = Convert.ToInt32(q.Value);
                                }
                            }
                            cmd.Parameters.Clear();
                        }
                        trans.Commit();
                    }
                    catch
                    {
                        trans.Rollback();
                        throw;
                    }
                }
            }
        }
        /// <summary>  
        /// 执行多条SQL语句，实现数据库事务。  
        /// </summary>  
        /// <param name="SQLStringList">SQL语句的哈希表（key为sql语句，value是该语句的MySqlParameter[]）</param>  
        public static void ExecuteSqlTranWithIndentity(Hashtable SQLStringList)
        {
            using (MySqlConnection conn = new MySqlConnection(connectionString))
            {
                conn.Open();
                using (MySqlTransaction trans = conn.BeginTransaction())
                {
                    MySqlCommand cmd = new MySqlCommand();
                    try
                    {
                        int indentity = 0;
                        //循环  
                        foreach (DictionaryEntry myDE in SQLStringList)
                        {
                            string cmdText = myDE.Key.ToString();
                            MySqlParameter[] cmdParms = (MySqlParameter[])myDE.Value;
                            foreach (MySqlParameter q in cmdParms)
                            {
                                if (q.Direction == ParameterDirection.InputOutput)
                                {
                                    q.Value = indentity;
                                }
                            }
                            PrepareCommand(cmd, conn, trans, cmdText, cmdParms);
                            int val = cmd.ExecuteNonQuery();
                            foreach (MySqlParameter q in cmdParms)
                            {
                                if (q.Direction == ParameterDirection.Output)
                                {
                                    indentity = Convert.ToInt32(q.Value);
                                }
                            }
                            cmd.Parameters.Clear();
                        }
                        trans.Commit();
                    }
                    catch
                    {
                        trans.Rollback();
                        throw;
                    }
                }
            }
        }
        /// <summary>  
        /// 执行一条计算查询结果语句，返回查询结果（object）。  
        /// </summary>  
        /// <param name="SQLString">计算查询结果语句</param>  
        /// <returns>查询结果（object）</returns>  
        public static object GetSingle(string SQLString, params MySqlParameter[] cmdParms)
        {
            using (MySqlConnection connection = new MySqlConnection(connectionString))
            {
                using (MySqlCommand cmd = new MySqlCommand())
                {
                    try
                    {
                        PrepareCommand(cmd, connection, null, SQLString, cmdParms);
                        object obj = cmd.ExecuteScalar();
                        cmd.Parameters.Clear();
                        if ((Object.Equals(obj, null)) || (Object.Equals(obj, System.DBNull.Value)))
                        {
                            return null;
                        }
                        else
                        {
                            return obj;
                        }
                    }
                    catch (MySql.Data.MySqlClient.MySqlException e)
                    {
                        throw e;
                    }
                }
            }
        }

        /// <summary>  
        /// 执行查询语句，返回MySqlDataReader ( 注意：调用该方法后，一定要对MySqlDataReader进行Close )  
        /// </summary>  
        /// <param name="strSQL">查询语句</param>  
        /// <returns>MySqlDataReader</returns>  
        public static MySqlDataReader ExecuteReader(string SQLString, params MySqlParameter[] cmdParms)
        {
            MySqlConnection connection = new MySqlConnection(connectionString);
            MySqlCommand cmd = new MySqlCommand();
            try
            {
                PrepareCommand(cmd, connection, null, SQLString, cmdParms);
                MySqlDataReader myReader = cmd.ExecuteReader(CommandBehavior.CloseConnection);
                cmd.Parameters.Clear();
                return myReader;
            }
            catch (MySql.Data.MySqlClient.MySqlException e)
            {
                throw e;
            }
            //          finally  
            //          {  
            //              cmd.Dispose();  
            //              connection.Close();  
            //          }     

        }

        /// <summary>  
        /// 执行查询语句，返回DataSet  
        /// </summary>  
        /// <param name="SQLString">查询语句</param>  
        /// <returns>DataSet</returns>  
        public static DataSet Query(string SQLString, params MySqlParameter[] cmdParms)
        {
            using (MySqlConnection connection = new MySqlConnection(connectionString))
            {
                MySqlCommand cmd = new MySqlCommand();
                PrepareCommand(cmd, connection, null, SQLString, cmdParms);
                using (MySqlDataAdapter da = new MySqlDataAdapter(cmd))
                {
                    DataSet ds = new DataSet();
                    try
                    {
                        da.Fill(ds, "ds");
                        cmd.Parameters.Clear();
                    }
                    catch (MySql.Data.MySqlClient.MySqlException ex)
                    {
                        throw new Exception(ex.Message);
                    }
                    return ds;
                }
            }
        }


        private static void PrepareCommand(MySqlCommand cmd, MySqlConnection conn, MySqlTransaction trans, string cmdText, MySqlParameter[] cmdParms)
        {
            if (conn.State != ConnectionState.Open)
                conn.Open();
            cmd.Connection = conn;
            cmd.CommandText = cmdText;
            if (trans != null)
                cmd.Transaction = trans;
            cmd.CommandType = CommandType.Text;//cmdType;  
            if (cmdParms != null)
            {


                foreach (MySqlParameter parameter in cmdParms)
                {
                    if ((parameter.Direction == ParameterDirection.InputOutput || parameter.Direction == ParameterDirection.Input) &&
                        (parameter.Value == null))
                    {
                        parameter.Value = DBNull.Value;
                    }
                    cmd.Parameters.Add(parameter);
                }
            }
        }

        /// <summary>
        /// table转json
        /// </summary>
        /// <param name="dt"></param>
        /// <returns></returns>
        public static string DataTableToJson(DataTable dt)
        {
            StringBuilder jsonBuilder = new StringBuilder();
            jsonBuilder.Append("{"Name":"" + dt.TableName + "","Rows");
            jsonBuilder.Append("":[");
            for (int i = 0; i < dt.Rows.Count; i++)
            {
                jsonBuilder.Append("{");
                for (int j = 0; j < dt.Columns.Count; j++)
                {
                    jsonBuilder.Append(""");
                    jsonBuilder.Append(dt.Columns[j].ColumnName);
                    jsonBuilder.Append("":"");
                    jsonBuilder.Append(dt.Rows[i][j].ToString().Replace(""", "\""));
                    jsonBuilder.Append("",");
                }
                jsonBuilder.Remove(jsonBuilder.Length - 1, 1);
                jsonBuilder.Append("},");
            }
            jsonBuilder.Remove(jsonBuilder.Length - 1, 1);
            jsonBuilder.Append("]");
            jsonBuilder.Append("}");
            return jsonBuilder.ToString();
        }
        /// <summary>
        /// dataset转Json
        /// </summary>
        /// <param name="ds"></param>
        /// <returns></returns>
        public static string DatasetToJson(DataSet ds)
        {
            StringBuilder json = new StringBuilder();
            json.Append("{"Tables":");
            json.Append("[");
            foreach (DataTable dt in ds.Tables)
            {
                json.Append(DataTableToJson(dt));
                json.Append(",");
            }
            json.Remove(json.Length - 1, 1);
            json.Append("]");
            json.Append("}");
            return json.ToString();
        }


    }

}