C#調用MySQL存儲過程

Sql代碼 
CREATE PROCEDURE `yuan_user_cc`(in xname varchar(100),in xemail varchar(100),in xpassword varchar(100),out xid integer) 
begin 
            insert into yuan_user(name,email,password)values(xname,xemail,xpassword); 
            select id into xid from yuan_user where name=xname; 
end 
 
C#代碼 
private string shuju_lianjie(string name, string email, string password) 
 { 
 
     Int16 id;//返回的id值 
     MySqlConnection mysqlcon; 
     MySqlDataAdapter mysqldata = new MySqlDataAdapter(); 
     DataSet dataset = new DataSet(); 
     mysqlcon = new MySqlConnection("server=localhost; user id=root; password=123; database=yuan_test; pooling=false;charset=gb2312"); 
     mysqldata.SelectCommand = new MySqlCommand(); 
     mysqldata.SelectCommand.Connection = mysqlcon; 
     mysqldata.SelectCommand.CommandText = "yuan_user_cc"; 
     mysqldata.SelectCommand.CommandType = CommandType.StoredProcedure; 
     //設置參數，添加到數據庫 
     MySqlParameter name_parameter = new MySqlParameter("?xname", MySqlDbType.VarChar,100);//mysql的存儲過程參數是以?打頭的！！！！ 
     name_parameter.Value = name; 
     mysqldata.SelectCommand.Parameters.Add(name_parameter); 
     //+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 
     MySqlParameter email_parameter = new MySqlParameter("?xemail", MySqlDbType.VarChar, 100);//mysql的存儲過程參數是以?打頭的！！！！ 
     email_parameter.Value = email; 
     mysqldata.SelectCommand.Parameters.Add(email_parameter); 
     //++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 
     MySqlParameter password_parameter = new MySqlParameter("?xpassword", MySqlDbType.VarChar, 100);//mysql的存儲過程參數是以?打頭的！！！！ 
     password_parameter.Value = password; 
     mysqldata.SelectCommand.Parameters.Add(password_parameter); 
     //++++++++++++++++++++++++++返回值++++++++++++++++++++++++++++++++++++++++++ 
     MySqlParameter id_parameter = new MySqlParameter("?xid", MySqlDbType.Int16,15);//mysql的存儲過程參數是以?打頭的！！！！ 
     id_parameter.Direction=ParameterDirection.Output; 
     mysqldata.SelectCommand.Parameters.Add(id_parameter); 
     //+++++++++++++++++++++++++打開數據庫，插入數據，返回id值+++++++++++++++++++ 
     try 
     { 
         mysqldata.Fill(dataset, "yuan_user_cc"); 
 
        id = (Int16)id_parameter.Value; 
         return id.ToString(); 
     } 
     catch (MySqlException ex) 
     { 
         MessageBox.Show(ex.Message); 
         return String.Empty; 
     }  
 
 
 }