string connStr = String.Format("server=127.0.0.1;user id=root; database=test; pooling=false;port=3306");
            MySqlConnection myConn = new MySqlConnection(connStr);
            myConn.Open();

            MySqlCommand cmd = new MySqlCommand();
            cmd.Connection = myConn;
            cmd.CommandType = CommandType.StoredProcedure;
            cmd.CommandText = "pre_name";
            MySqlParameter ind = new MySqlParameter("?index_name", MySqlDbType.Int16, 15);
            ind.Value=1;
            cmd.Parameters.Add(ind);
            MySqlParameter id = new MySqlParameter("?",MySqlDbType.VarChar,40);
            id.Direction = ParameterDirection.Output;
            cmd.Parameters.Add(id);
            cmd.ExecuteNonQuery();
            textBox4.Text = id.Value.ToString();


            myConn.Close();