C#调用MySQL存储过程

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

       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;
            //设置参数，添加到数据库
            MySqlParameter name_parameter = new MySqlParameter("?xname", MySqlDbType.VarChar,100);//mysql的存储过程参数是以?打头的！！！！
            name_parameter.Value = name;
            mysqldata.SelectCommand.Parameters.Add(name_parameter);
            //+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
            MySqlParameter email_parameter = new MySqlParameter("?xemail", MySqlDbType.VarChar, 100);//mysql的存储过程参数是以?打头的！！！！
            email_parameter.Value = email;
            mysqldata.SelectCommand.Parameters.Add(email_parameter);
            //++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
            MySqlParameter password_parameter = new MySqlParameter("?xpassword", MySqlDbType.VarChar, 100);//mysql的存储过程参数是以?打头的！！！！
            password_parameter.Value = password;
            mysqldata.SelectCommand.Parameters.Add(password_parameter);
            //++++++++++++++++++++++++++返回值++++++++++++++++++++++++++++++++++++++++++
            MySqlParameter id_parameter = new MySqlParameter("?xid", MySqlDbType.Int16,15);//mysql的存储过程参数是以?打头的！！！！
            id_parameter.Direction=ParameterDirection.Output;
            mysqldata.SelectCommand.Parameters.Add(id_parameter);
            //+++++++++++++++++++++++++打开数据库，插入数据，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;
            } 


        }