Why is this variable being reset?

Here is my code. I dont understand why the string varialbe "menuCode" is getting reset when the ddlItemCategories_SelectedIndexChanged is called.

Imports System.Data.SqlClient
Public Class menu
 Inherits System.Web.UI.Page
 Private conn As SqlConnection
 Protected WithEvents dlDinnerCategrories As System.Web.UI.WebControls.DataList
 Protected WithEvents dgItems As System.Web.UI.WebControls.DataGrid
 Private cmd As SqlCommand
 Protected menuCode As String
 Protected WithEvents lbtnDinner As System.Web.UI.WebControls.LinkButton
 Protected WithEvents lbtnLunch As System.Web.UI.WebControls.LinkButton
 Protected WithEvents ddlItemCategories As System.Web.UI.WebControls.DropDownList
 Protected WithEvents lblDebug As System.Web.UI.WebControls.Label
 Private categorycode As String
#Region " Web Form Designer Generated Code "
 'This call is required by the Web Form Designer.
 <System.Diagnostics.DebuggerStepThrough()> Private Sub InitializeComponent()
 End Sub
 'NOTE: The following placeholder declaration is required by the Web Form Designer.
 'Do not delete or move it.
 Private designerPlaceholderDeclaration As System.Object
 Private Sub Page_Init(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Init
 'CODEGEN: This method call is required by the Web Form Designer
 'Do not modify it using the code editor.
 InitializeComponent()
 End Sub
#End Region
 Private Sub Page_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
 End Sub
 Private Sub getItemCategories()
 Dim commandText As String
 Dim cmd As SqlCommand
 Dim dr As SqlDataReader
 Dim item As ListItem
 If ConnectToDatabase(conn) Then
 If menuCode.Equals("DI") Or menuCode.Equals("LU") Then
 commandText = "SELECT Code, Category FROM ItemCategories WHERE Menu = '" & menuCode & "' OR Menu = 'DL'"
 Else
 commandText = "SELECT Code, Category FROM ItemCategories WHERE Menu = '" & menuCode & "'"
 End If
 cmd = New SqlCommand(commandText, conn)
 dr = cmd.ExecuteReader(CommandBehavior.CloseConnection)
 While dr.Read()
 item = New ListItem(dr.GetValue(1), dr.GetValue(0))
 ddlItemCategories.Items.Add(item)
 End While
 End If
 lblDebug.Text = menuCode
 End Sub
 Function ConnectToDatabase(ByRef conn As SqlConnection) As Boolean
 Dim connectionString As String
 Dim ok As Boolean = False
 Try
 connectionString = "Data Source=mssql07;Initial Catalog=DB_120551;User ID=steamerssto;Password=steamers"
 conn = New SqlConnection(connectionString)
 conn.Open()
 'Response.Write("Opened database")
 ok = True
 Catch ex As Exception
 'Response.Write("" & ex.Message)
 conn.Close()
 conn.Dispose()
 End Try
 Return ok
 End Function
 Private Sub ddlDinnerCategories_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs)
 End Sub
 Private Sub lbtnDinner_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles lbtnDinner.Click
 ddlItemCategories.Items.Clear()
 menuCode = "DI"
 getItemCategories()
 End Sub
 Private Sub lbtnLunch_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles lbtnLunch.Click
 ddlItemCategories.Items.Clear()
 menuCode = "LU"
 getItemCategories()
 End Sub
 Private Sub ddlItemCategories_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ddlItemCategories.SelectedIndexChanged
 'getItems()
 lblDebug.Text = menuCode
 End Sub
 Private Sub getItems()
 Dim commandText As String
 Dim cmd As SqlCommand
 If ConnectToDatabase(conn) Then
 If menuCode.Equals("DI") Or menuCode.Equals("LU") Then
 commandText = "SELECT Title, Description, Price FROM Items WHERE Category = '" & ddlItemCategories.SelectedValue & "' AND Menu = '" & menuCode & "' OR Menu = 'DL'"
 Else
 commandText = "SELECT Title, Description, Price FROM Items WHERE Category = '" & ddlItemCategories.SelectedValue & "' AND Menu = '" & menuCode & "'"
 End If
 cmd = New SqlCommand(commandText, conn)
 lblDebug.Text = commandText
 dgItems.DataSource = cmd.ExecuteReader(CommandBehavior.CloseConnection)
 dgItems.DataBind()
 End If
 End Sub
End Class

Because you are doing a post back but not saving the value of the string between postbacks

MajorCats
hey

looks like menuCode only gets set after clicking 'Lunch' or 'Dinner' buttons so if you try to select something from the dropdownlist before clicking one of the buttons you'll get a null value.
How do I go about fixing this problem? See, they need to choose what menu they want first. Then menuCode is set and used to get the appropriate subcategories for the drop down list.

Thanks
Jarrod
Nevermind I figured it out. Had to learn how to use ViewState.

Thanks for the hints though.

Jarrod