Unhandled Exception Handler Changes in .NET 2.0

Provided by Dave Juth, Senior Systems Architect

WinForms applications written in .NET 1.x and converted to .NET 2.0 that have a global unhandled exception handler need to be modified to trap the exception.

An example of the 1.x way to implement a global exception handler follows:

(in Sub Main):

    AddHandler Application.ThreadException, AddressOf OnThreadException

The exception handler:

 

    Public Sub OnThreadException(ByVal sender As Object, _

        ByVal t As System.Threading.ThreadExceptionEventArgs)

 

        LogError(t.Exception)

        Application.Exit()

 

    End Sub

 

In .NET 2.0, this code will not trap the exception. The .NET 2.0 framework requires hooking AppDomain.CurrentDomain.UnhandledException instead:

(in Sub Main):

    AddHandler AppDomain.CurrentDomain.UnhandledException, _

        AddressOf OnUnhandledException

The exception handler itself can be implemented as shown below:

      Public Sub OnUnhandledException(ByVal sender As Object, _

          ByVal t As UnhandledExceptionEventArgs)

 

          Logger.LogError(t.ExceptionObject)

          Application.Exit()

 

      End Sub