WebException Throws NullReferenceException

Spilled · #1 (**permalink**) 12-02-2008, 2:51 AM

Hello all when I try to Handle my WebException I'm getting a NullReferenceException when I try to Display the Error. Here is my code:

Code:

            Try
                res = req.GetResponse()
                RaiseEvent UpdateResponse(threadID, res.StatusCode.ToString & " - " & res.StatusDescription)
                res.Close()
            Catch Err As WebException
                If Err.Status = WebExceptionStatus.ProtocolError Then
                    RaiseEvent UpdateResponse(threadID, "401 - Unauthorised")
                Else
                    RaiseEvent UpdateResponse(threadID, CType(Err.Response, HttpWebResponse).StatusCode.ToString & " - " & CType(Err.Response, HttpWebResponse).StatusDescription)
                    RetryComboNeedNewProxy = True
                End If
            End Try

RaiseEvent UpdateResponse(threadID, CType(Err.Response, HttpWebResponse).StatusCode.ToString & " - " & CType(Err.Response, HttpWebResponse).StatusDescription)
Is where i get the NullReferenceException, Err.response is "nothing" in the debugger, WebException.Response suppose to return the WebResponse type of the exception? Thanks in advance.

jmcilhinney · #2 (**permalink**) 12-02-2008, 5:40 AM

The documentation indicates that if the Status IS ProtocolError then Response will contain a WebResponse. You're trying to get Response when Status is NOT ProtocolError, in which case it's obviously not guaranteed to not be Nothing.

Spilled · #3 (**permalink**) 12-02-2008, 6:13 AM

o ic, so what is the response when it is NOT protocol error? A timeout?

jmcilhinney · #4 (**permalink**) 12-02-2008, 6:32 AM

Um, obviously in your case it's Nothing. Have you checked what the actual status is? Maybe that will give you a clue what the issue is. After all, for some errors it should be obvious that there'd be no response because the server couldn't have responded.

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