How to check if asp session is valid?

Question

Hi, Im using outproc session that is managed by aspnet_state. Sometimes I get run time errors saying that the session is invalid. So I wanted to check if the session is valid for every request I make. But I couldn't find a proper way to do it like in this Question using Java.

Here is the code I'm using right now in the page_preinit event.It looks ugly but it works.

            Try
                Dim x = Session.Keys().Item(0)
            Catch ex As Exception
                Session.Clear()
            End Try

Does any one knows a better approach?

Thanks

Answer 1

You could try checking the context object.

C#

if(Context.Session != null)
{
    //Redirect to login page etc
}

VB (Used a C# to VB converter here..not sure if this is correct)

If Context.Session IsNot Nothing Then
    'Redirect to login page etc
End If

If you are using forms authentication and it is setup correctly, it should redirect for you. If you still need to be explicit, I would recommend placing this type of code in the Global.asax, or a base class that each of your pages could derive from, rather than adding it to every request.

Answer 2

Actually I solved the problem by checking the first element of the session( session.item(0) ) I put the code in try catch . if the there is an exception I just clear the session. This code is in a basepage for all my pages.

so in the preinit event my code look like this

Private Sub Page_PreInit(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.PreInit
    Try
     Dim x = Session.Keys().Item(0)
    Catch ex As Exception
     Session.Clear()
    End Try
End Sub

It seems to be ugly but it does solve my problem.

Thanks everyone.

Answer 3

Just check the Session.Count instead of attempting to access the first item in an error handling block...