在Mysql中调用Read（）之前无法尝试访问字段

Question

使用存储过程将新记录插入MySQL数据库时发生以下异常。

  

在调用Read（）

之前无效尝试访问字段

我的代码在这里：

protected string InsertDoctype(string ioption, int icategory_id, string icategory_name, string iUSERID,string iGUID)
{

    string iresult =string.Empty;
    try
    {

        conString.Open();

        MySqlCommand cmd = new MySqlCommand("sp_b1_Doctype", conString);
        cmd.CommandType = System.Data.CommandType.StoredProcedure;


        cmd.Parameters.Add("?ioption", MySqlDbType.VarChar).Value = ioption;
        cmd.Parameters.Add("?icategory_id", MySqlDbType.Int32).Value = icategory_id;
        cmd.Parameters.Add("?icategory_name", MySqlDbType.VarChar).Value = icategory_name;
        cmd.Parameters.Add("?iUSERID", MySqlDbType.VarChar).Value = iUSERID;
        cmd.Parameters.Add("?iGUID", MySqlDbType.VarChar).Value = iGUID;         

        cmd.Parameters.Add(new MySqlParameter("?oresult", MySqlDbType.VarChar));
        cmd.Parameters["?oresult"].Direction = ParameterDirection.Output;

        cmd.ExecuteNonQuery();

        iresult = cmd.Parameters["?oresult"].Value.ToString();

    }
    catch (Exception Ex)
    {


    }
    finally
    {
        if (conString.State == ConnectionState.Open)
            conString.Close();
    }

    return iresult;

}

请帮帮我。

存储过程在这里：

  CREATE DEFINER=`root`@`%` PROCEDURE `sp_b1_Doctype`(in ioption varchar(10),in icategory_id integer,in icategory_name varchar(45),in iUSERID varchar(8),in iGUID varchar(45), out oresult varchar (100))
BEGIN



 -- Declare variables to hold diagnostics area information
 DECLARE code CHAR(5) DEFAULT '00000';
 DECLARE msg TEXT;
 DECLARE rows INT;
 DECLARE result TEXT;

 -- Declare exception handler for failed insert
 DECLARE CONTINUE HANDLER FOR SQLEXCEPTION
BEGIN
  GET DIAGNOSTICS CONDITION 1
    code = RETURNED_SQLSTATE, msg = MESSAGE_TEXT;
END;

 -- Perform the insert
IF ioption="insert" THEN

set autocommit = 0;
start transaction;

insert into b1_category(category_id, category_name, USERID, INS_DATE, GUID) values (icategory_id, icategory_name, iUSERID, now(), iGUID);

SET result ="Insert succeeded";

END IF;





 IF code = '00000' THEN
 GET DIAGNOSTICS rows = ROW_COUNT;
 ELSE
 -- SET result = CONCAT('insert failed, error = ',code,', message = ',msg,'$e');
 SET result = "Something went wrong. Please try again later ..$e";
 END IF;

 SET oresult = result;

   commit;

  END