Posted on: 9/29/2014 8:11:43 PM | Views : 362

When this line of code in the code behind of a web form 
PushPageStack(Me) calls this sub procedure
Public Sub PushPageStack(ByVal current As Page) Try Dim PageStack As Stack = current.Session("PageStack") ' NOTE: This assumes that all pages are in the same folder PageStack.Push(System.IO.Path.GetFileName(current.Request.Path)) current.Session("PageStack") = PageStack Catch ex As Exception Elmah.ErrorSignal.FromCurrentContext().Raise(ex) End Try End Sub it generates this exception
<error application=..." host="SS2-002" type="System.NullReferenceException" message="Object reference not set to an instance of an object." source="Book" detail="System.NullReferenceException: Object ref ...

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