When option in Try...Catch

Paul Vick explain how you can use the option When in a Try...Catch to execute some action when you have an exception (like logging the exception)

Instead of:

Sub DoWork()
  Try
    ' Do some work
  Catch ex As Exception
    LogException(ex)
    Throw
  End Try
End Sub

Use:

Sub DoWork()
  Try
    ' Do some work
  Catch ex As Exception When LogException(ex)
    ' Do no work
  End Try
End Sub

Read more here