Variable loses scope when used through button.click handler - asp.net

Question

When I call my function at Me.Load everything is OK, but when I trigger my function only on the button click event all variables inside lose their set values. I just started on VB.NET so I don't fully understand scope nature here.
Here is my code:
Public Class WorkflowForward
Inherits FileBound.Web.FBBasePage
' Private decalrations
Private cfile_id As String = "" ' Current files ID
Private FBProject As Project = Nothing ' FileBound Project object
Private cmd As String = "" ' SQL query string
Private FBFile As FileBound.File = Nothing ' Filebound file holder
Private FBRoutes As RouteCollection = Nothing ' FileBound route collection holder
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
' Set SqlDataSource connection string
FBSqlDataSource.ConnectionString = ConfigurationManager.ConnectionStrings("FB_0371tcc").ConnectionString
If Not Me.IsPostBack Then
' Set values to variables
Page_setup() ' Here I set values to variabels
setRoute_debug("Admin1 Test")
End If
End Sub
Protected Sub sendEmail_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles sendEmail.Click
' CAN I HAZ SOME TEST????
'setRoute_debug(emailTo.SelectedValue.ToString)
Response.Write("<script>" & Me.FBRoutes.TotalCount.ToString & "</script>")
End Sub
Private Sub setRoute_debug(ByVal route_to As String)
' IF WE HAZ SOME ITEMS FINISH THEM MUHUHAHHAHAHA
If FBBusiness.LoggedInUser.RoutedItems.TotalCount > 0 Then
For Each item As RoutedItem In FBBusiness.LoggedInUser.RoutedItems
item.Complete("Completed!")
Next
End If
' DEBUG MODE #YOLO
' I'VE DONE IT I CAN HAZ ROUTEZ
For Each r As Route In Me.FBRoutes
If r.Name = route_to Then
For Each doc As FileBound.Document In FBFile.Documents
doc.Route(r.ID)
Next
End If
Next
End Sub
Private Sub Page_setup()
' Some code that sets values
End Sub
End Class
When I click the button it throws this error:
Object reference not set to an instance of an object.
Line 46: Response.Write("<script>" & Me.FBRoutes.TotalCount.ToString & "</script>")

Answer 1

A button click on as asp.net page would come as a PostBack.
Your are setting up the page only in
If Not Me.IsPostBack
This is fine for asp.net controls, cause they retain their state across PostBacks using the ViewState.
When click a button, server receives a new request, and a new object of Page is created. Your variables are not set for this object.
Set your page level variables on every PostBack, like this
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
' Set SqlDataSource connection string
FBSqlDataSource.ConnectionString = ConfigurationManager.ConnectionStrings("FB_0371tcc").ConnectionString
Page_setup() ' Here I set values to variables
If Not Me.IsPostBack Then
'Set Page level control values like TextBox values
End If
End Sub