c#调用Mysql带参数的存储过程

DELIMITER $$  
  
USE `bookshop`$$  
  
DROP PROCEDURE IF EXISTS `proc_bookinfo`$$  
  
CREATE DEFINER=``@`` PROCEDURE `proc_bookinfo`(IN ispay VARCHAR(10),OUT unPaycount INT)  
BEGIN  
 SELECT COUNT(*) INTO unPaycount FROM tb_bookinfo AS a,tb_shopbook AS b WHERE b.ispay=ispay;  
 END$$  
  
DELIMITER ; 

StringBuilder sql=new StringBuilder();  
sql.Append("proc_bookinfo");  
           MySqlParameter[] parameters = {  
                   new MySqlParameter("@ispay", MySqlDbType.VarChar,10),  
                   new MySqlParameter("@unPaycount", MySqlDbType.Int32,11)  
                                         };  
           parameters[0].Value ="未付款";  
           parameters[0].Direction = ParameterDirection.Input;  
           parameters[1].Value = 0 ;  
           parameters[1].Direction = ParameterDirection.Output;  
           DbHelperMySQL.ExecuteProc(Convert.ToString(sql), parameters);

    public static object ExecuteProc(string SQLString, params MySqlParameter[] cmdParms)  
            {  
                using (MySqlConnection connection = new MySqlConnection(connectionString))  
                {  
                    using (MySqlCommand cmd = new MySqlCommand())  
                    {  
                        try  
                        {  
                              
                            PrepareCommand(cmd, connection, null, SQLString, cmdParms);  
                            cmd.CommandType = CommandType.StoredProcedure;  
                            int rows = cmd.ExecuteNonQuery();  
                            Console.WriteLine("返回值为 "+cmdParms[1].Value);  
                            cmd.Parameters.Clear();  
                            return rows;  
                        }  
                        catch (MySql.Data.MySqlClient.MySqlException e)  
                        {  
                            connection.Close();  
                            throw e;  
                        }  
                    }  
                }  
            }