"Carl" wrote:
> I know that you should not update the applications GUI with code running in
> the BackgroundWorker thread (or any other thread). But is it OK to
> construct, show and update new Forms inside the thread? The difference I'm
> trying to point out is that you don't update any existing GUI, but instead,
> create (of example) a new small form with a progress indicator, OK?

"Rob" <Rob@discussions.microsoft.com> wrote in message
news:F0EDE161-85AC-4515-B7BC-CF9C4BC99674@microsoft.com...
> "Carl" wrote:
>> I know that you should not update the applications GUI with code running
>> in
>> the BackgroundWorker thread (or any other thread). But is it OK to
>> construct, show and update new Forms inside the thread? The difference
>> I'm
>> trying to point out is that you don't update any existing GUI, but
>> instead,
>> create (of example) a new small form with a progress indicator, OK?
>
> Yes and no.
>
> Yes: WinForms GUI objects are bound to the thread they are created on and
> can be updated from that thread. It doesn't matter if that thread is the
> main UI thread or a secondary thread, so long as the thread is consistent.
>
> No: This can't be done on a BackgroundWorker thread. WinForms UI needs to
> be on an STA thread, and BackgroundWorkers are MTA. Any UI thread will
> have
> to pump messages, so the thread will need to call Application.Run or
> Form.ShowDialog to activate a message pump.
>
> In general, it's best to keep the UI on the main thread and have the
> BackgroundWorker periodically call ReportProgress to let the UI thread
> know
> to update the progress bar.
>
> --Rob
>