Page Level variables and PostBacks

I have the following code at the top of my page.  1 using System;
2 using System.Collections.Generic;
3 using System.Linq;
4 using System.Web;
5 using System.Web.UI;
6 using System.Web.UI.WebControls;
7 using System.Data;
8 using System.Data.SqlClient;
9 using IngredientDALTableAdapters;
10
11
12 public partial class CreateMixingRecord : System.Web.UI.Page
13 {
14 // following deals w ...