Question

asp.net调用mysql存储过程

mycomm = new MySqlCommand("sp_luckdraw", myco);

mycomm.CommandType = CommandType.StoredProcedure;

MySqlParameter myParameter = new MySqlParameter("@prizeCode",MySqlDbType.VarChar, 50);
myParameter.Value = strValue.ToUpper();
myParameter.Direction = ParameterDirection.Input;
mycomm.Parameters.Add(myParameter);

MySqlParameter myParameter2 = new MySqlParameter("@result", MySqlDbType.Int32);
myParameter2.Direction = ParameterDirection.Output;
mycomm.Parameters.Add(myParameter2);

using (dr = mycomm.ExecuteReader(CommandBehavior.CloseConnection))
{
string strResult1 = myParameter2.Value.ToString();
while (dr.Read())
{
string strResult = dr["result"].ToString();
}
}

请我为什么传出参数myParameter2.Value是null，怎么解决。（存储过程在mysql数据库执行没问题）

Answer 1

类的调用方法：
public int RunProcedure(string storedProcName, IDataParameter[] parameters, out int rowsAffected)
{
using (SqlConnection connection = new SqlConnection(strConn))
{
int result;
connection.Open();
SqlCommand command = BuildIntCommand(connection, storedProcName, parameters);
rowsAffected = command.ExecuteNonQuery();
result = (int)command.Parameters["ReturnValue"].Value;
//Connection.Close();
return result;
}
}
Mysql的简单存储过程：

CREATE PROCEDURE `DELETEDB`(IN m_orgid char(12))
BEGIN
delete from hardwareinfo where orgid=m_orgid;
delete from addressinfo where orgid=m_orgid;
END

Answer 2

你执行的方式也许有问题，试试下面的

//把using那段全部替换为
mycomm.ExecuteNonQuery();
string strResult1 = myParameter2.Value.ToString();

 如果上述代码不行，再在mysql里直接执行存储过程看返回值到底是什么。