c# 操作MySql数据库类

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c# 操作MySql数据库类

public class MySqlConnect
    {
		//server  数据库地址
		//user id  用户名
		//password  密码
		//persist security info  是否启用线程池
		//database  数据库名


        private static string conn_string = "server=localhost;user id=root;password=123456;persist security info=True;database=softwarelibrary";
//空构造
        public MySqlConnect()
        {

        }
        /// <summary>
        /// 构造函数 初始化连接字符串
        /// </summary>
        /// <param name="conn_str">连接字符串/param>
        public MySqlConnect(string conn_str)
        {
            conn_string = conn_str;
        }

        /// <summary>
        /// 打开数据库连接
        /// </summary>
        /// <param name="cnn">数据库连接对象</param>
        private static void Open(MySqlConnection cnn)
        {
            if (cnn.State == ConnectionState.Closed)
            {
                cnn.Open();
            }
        }

        /// <summary>
        /// 关闭数据库连接
        /// </summary>
        /// <param name="cnn">数据库连接对象</param>
        private static void Close(MySqlConnection cnn)
        {
            if (cnn != null)
            {
                if (cnn.State == ConnectionState.Open)
                {
                    cnn.Close();
                }
                cnn.Dispose();
            }
        }
        /// <summary>
        /// 查询一个结果
        /// </summary>
        /// <param name="strSql">sql语句</param>
        /// <param name="pms">参数</param>
        /// <returns>返回结果</returns>
        public static object ExecuteScalar(string strSql,params MySqlParameter[] pms)
        {
            MySqlConnection cnn = new MySqlConnection(conn_string);
            MySqlCommand cmd = new MySqlCommand();
            try
            {
                Open(cnn);
                cmd = new MySqlCommand(strSql, cnn);
                if (pms != null)
                {
                    cmd.Parameters.AddRange(pms);
                }
                return cmd.ExecuteScalar();
            }
            catch (Exception e)
            {
                System.Windows.Forms.MessageBox.Show(e.Message);
            }
            finally
            {
                cmd.Dispose();
                Close(cnn);
            }
            return null;
        }

        /// <summary>
        /// 执行查询语句(返回MySqlDataAdapter)
        /// </summary>
        /// <param name="strSql">sql语句</param>
        /// <param name="pms">参数</param>
        /// <returns>MySqlDataAdapter</returns>
        public static MySqlDataReader ExecuteReader(string strSql, params MySqlParameter[] pms)
        {
            MySqlConnection cnn = new MySqlConnection(conn_string);
            MySqlCommand cmd = new MySqlCommand();
            try
            {
                Open(cnn);
                cmd = new MySqlCommand(strSql, cnn);
                if (pms != null)
                {
                    cmd.Parameters.AddRange(pms);
                }
                return cmd.ExecuteReader(CommandBehavior.CloseConnection);
            }
            catch (Exception e)
            {
                throw new Exception(e.Message);
            }
            finally
            {
                cmd.Dispose();
            }
        }

        /// <summary>
        /// 查询（DataSet）
        /// </summary>
        /// <param name="strSql">SQL语句</param>
        /// <returns>查询结果:DataSet</returns>
        /// foreach (DataRow item in dt.Rows){ }
        public static DataTable GetDataTable(string strSql, params MySqlParameter[] pms)
        {
            MySqlConnection cnn = new MySqlConnection(conn_string);
            MySqlDataAdapter sda = new MySqlDataAdapter();
            try
            {
                Open(cnn);
                sda = new MySqlDataAdapter(strSql, cnn);
                if (pms != null)
                {
                    sda.SelectCommand.Parameters.AddRange(pms);
                }
                DataTable dt = new DataTable();
                sda.Fill(dt);
                return dt;
            }
            catch (Exception e)
            {
                System.Windows.Forms.MessageBox.Show(e.Message);
                return null;
            }
            finally
            {
                sda.Dispose();
                Close(cnn);
            }
        }

        /// <summary>
        /// 增加,删除,修改
        /// </summary>
        /// <param name="strSql">sql语句</param>
        /// <param name="pms">参数</param>
        /// <returns>返回受影响的行数。</returns>
        public static int ExecuteNonQuery(string strSql, params MySqlParameter[] pms)
        {
            MySqlConnection cnn = new MySqlConnection(conn_string);
            MySqlCommand cmd = new MySqlCommand();
            try
            {
                Open(cnn);
                cmd = new MySqlCommand(strSql, cnn);
                if (pms != null)
                {
                    cmd.Parameters.AddRange(pms);
                }
                return cmd.ExecuteNonQuery();
            }
            catch (Exception e)
            {
                System.Windows.Forms.MessageBox.Show(e.Message);
                return 0;
            }
            finally
            {
                cmd.Dispose();
                Close(cnn);
            }

        }

    }