[转]MySQLHelper类

本文转自：http://de.cel.blog.163.com/blog/static/5145123620110181003903/

类似于SQLHelper，只是这里引用的是MySql.Data类库，而不是System.Data.SqlClient;因为.Net框架里面并不包含些类库，好在咱们有强大的网友有做好的MySql.Data类库。在网上一搜MySql.Data就可以找到的。注意一定要先添加对MySql.Data的引用哦，接下来是MySQLHelper的类库代码。

using System.Data;
using MySql.Data.MySqlClient;


namespace MySQLHelper
{

    /// <summary>

    /// 基于MySQL的数据层基类

    /// </summary>

    /// <remarks>

    /// 参考于MS Petshop 4.0

    /// </remarks>

    public abstract class MySqlHelper
    {

        #region 数据库连接字符串

        public static readonly string DBConnectionString = System.Configuration.ConfigurationManager.ConnectionStrings["DBConnectionString"].ToString();

        //public static readonly string DBConnectionString = "Server=localhost;DataBase=menagerie;Uid=de.cel;Pwd=de.cel";   //在MySql中localhost好像不能用"."代替，我试了一下，会出错。
        #endregion

        #region PrepareCommand

        /// <summary>

        /// Command预处理

        /// </summary>

        /// <param name="conn">MySqlConnection对象</param>

        /// <param name="trans">MySqlTransaction对象，可为null</param>

        /// <param name="cmd">MySqlCommand对象</param>

        /// <param name="cmdType">CommandType，存储过程或命令行</param>

        /// <param name="cmdText">SQL语句或存储过程名</param>

        /// <param name="cmdParms">MySqlCommand参数数组，可为null</param>

        private static void PrepareCommand(MySqlConnection conn, MySqlTransaction trans, MySqlCommand cmd, CommandType cmdType, 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 = cmdType;

            if (cmdParms != null)
            {

                foreach (MySqlParameter parm in cmdParms)

                    cmd.Parameters.Add(parm);

            }

        }

        #endregion

        #region ExecuteNonQuery

        /// <summary>

        /// 执行命令

        /// </summary>

        /// <param name="connectionString">数据库连接字符串</param>

        /// <param name="cmdType">命令类型（存储过程或SQL语句）</param>

        /// <param name="cmdText">SQL语句或存储过程名</param>

        /// <param name="cmdParms">MySqlCommand参数数组</param>

        /// <returns>返回受引响的记录行数</returns>

        public static int ExecuteNonQuery(string connectionString, CommandType cmdType, string cmdText, params MySqlParameter[] cmdParms)
        {

            MySqlCommand cmd = new MySqlCommand();

            using (MySqlConnection conn = new MySqlConnection(connectionString))
            {

                PrepareCommand(conn, null, cmd, cmdType, cmdText, cmdParms);

                int val = cmd.ExecuteNonQuery();

                cmd.Parameters.Clear();

                return val;

            }

        }

        /// <summary>

        /// 执行命令

        /// </summary>

        /// <param name="conn">Connection对象</param>

        /// <param name="cmdType">命令类型（存储过程或SQL语句）</param>

        /// <param name="cmdText">SQL语句或存储过程名</param>

        /// <param name="cmdParms">MySqlCommand参数数组</param>

        /// <returns>返回受引响的记录行数</returns>

        public static int ExecuteNonQuery(MySqlConnection conn, CommandType cmdType, string cmdText, params MySqlParameter[] cmdParms)
        {

            MySqlCommand cmd = new MySqlCommand();

            PrepareCommand(conn, null, cmd, cmdType, cmdText, cmdParms);

            int val = cmd.ExecuteNonQuery();

            cmd.Parameters.Clear();

            return val;

        }

        /// <summary>

        /// 执行事务

        /// </summary>

        /// <param name="trans">MySqlTransaction对象</param>

        /// <param name="cmdType">命令类型（存储过程或SQL语句）</param>

        /// <param name="cmdText">SQL语句或存储过程名</param>

        /// <param name="cmdParms">MySqlCommand参数数组</param>

        /// <returns>返回受引响的记录行数</returns>

        public static int ExecuteNonQuery(MySqlTransaction trans, CommandType cmdType, string cmdText, params MySqlParameter[] cmdParms)
        {

            MySqlCommand cmd = new MySqlCommand();

            PrepareCommand(trans.Connection, trans, cmd, cmdType, cmdText, cmdParms);

            int val = cmd.ExecuteNonQuery();

            cmd.Parameters.Clear();

            return val;

        }

        #endregion

        #region ExecuteScalar

        /// <summary>

        /// 执行命令，返回第一行第一列的值

        /// </summary>

        /// <param name="connectionString">数据库连接字符串</param>

        /// <param name="cmdType">命令类型（存储过程或SQL语句）</param>

        /// <param name="cmdText">SQL语句或存储过程名</param>

        /// <param name="cmdParms">MySqlCommand参数数组</param>

        /// <returns>返回Object对象</returns>

        public static object ExecuteScalar(string connectionString, CommandType cmdType, string cmdText, params MySqlParameter[] cmdParms)
        {

            MySqlCommand cmd = new MySqlCommand();

            using (MySqlConnection connection = new MySqlConnection(connectionString))
            {

                PrepareCommand(connection, null, cmd, cmdType, cmdText, cmdParms);

                object val = cmd.ExecuteScalar();

                cmd.Parameters.Clear();

                return val;

            }

        }

        /// <summary>

        /// 执行命令，返回第一行第一列的值

        /// </summary>

        /// <param name="connectionString">数据库连接字符串</param>

        /// <param name="cmdType">命令类型（存储过程或SQL语句）</param>

        /// <param name="cmdText">SQL语句或存储过程名</param>

        /// <param name="cmdParms">MySqlCommand参数数组</param>

        /// <returns>返回Object对象</returns>

        public static object ExecuteScalar(MySqlConnection conn, CommandType cmdType, string cmdText, params MySqlParameter[] cmdParms)
        {

            MySqlCommand cmd = new MySqlCommand();

            PrepareCommand(conn, null, cmd, cmdType, cmdText, cmdParms);

            object val = cmd.ExecuteScalar();

            cmd.Parameters.Clear();

            return val;

        }

        #endregion

        #region ExecuteReader

        /// <summary>

        /// 执行命令或存储过程，返回MySqlDataReader对象

        /// 注意MySqlDataReader对象使用完后必须Close以释放MySqlConnection资源

        /// </summary>

        /// <param name="connectionString">数据库连接字符串</param>

        /// <param name="cmdType">命令类型（存储过程或SQL语句）</param>

        /// <param name="cmdText">SQL语句或存储过程名</param>

        /// <param name="cmdParms">MySqlCommand参数数组</param>

        /// <returns></returns>

        public static MySqlDataReader ExecuteReader(string connectionString, CommandType cmdType, string cmdText, params MySqlParameter[] cmdParms)
        {

            MySqlCommand cmd = new MySqlCommand();

            MySqlConnection conn = new MySqlConnection(connectionString);

            try
            {

                PrepareCommand(conn, null, cmd, cmdType, cmdText, cmdParms);

                MySqlDataReader dr = cmd.ExecuteReader(CommandBehavior.CloseConnection);

                cmd.Parameters.Clear();

                return dr;

            }

            catch
            {

                conn.Close();

                throw;

            }

        }

        #endregion

        #region ExecuteDataSet

        /// <summary>

        /// 执行命令或存储过程，返回DataSet对象

        /// </summary>

        /// <param name="connectionString">数据库连接字符串</param>

        /// <param name="cmdType">命令类型(存储过程或SQL语句)</param>

        /// <param name="cmdText">SQL语句或存储过程名</param>

        /// <param name="cmdParms">MySqlCommand参数数组(可为null值)</param>

        /// <returns></returns>

        public static DataSet ExecuteDataSet(string connectionString, CommandType cmdType, string cmdText, params MySqlParameter[] cmdParms)
        {

            MySqlCommand cmd = new MySqlCommand();

            using (MySqlConnection conn = new MySqlConnection(connectionString))
            {

                PrepareCommand(conn, null, cmd, cmdType, cmdText, cmdParms);

                MySqlDataAdapter da = new MySqlDataAdapter(cmd);

                DataSet ds = new DataSet();

                da.Fill(ds);

                conn.Close();

                cmd.Parameters.Clear();

                return ds;

            }

        }

        #endregion

    }//end class

}