Re: Problem with threads

Thanks but this wouldn't solve my problem. I don't want to touch c++.

As far as I understand it correctly, the problem is that all the child windows 
(pointers to them) are stored in the c++ part of wxnet. When I call the 
wx.Frame C# destructor, it calls the underlaying c++ destructor which takes 
all the children and destroys them (in c++). So, when I overload the 
wx.Button destructor (or Dispose or whatever) which is wx.Frame's child in C# 
it's pretty useless because it's never called, right?

How do we solve this? If it's really like this the entire wx-net wrapper is 
useless :-(

Radek

> > Consider the following case:
> > I create a window with a button inside.
> > I create a thread that contains an endless loop which updates the
> > button's caption periodically.
> > When I close the window, I get an exception (null pointer in wx-native
> > code) which is 100% correct because by the time I call the button.text
> > (or whatever), the button does not exist.
> >
> > I know I have to stop the thread first but the problem is that I don't
> > know how to do it (WHERE to do it). I've tried the wx.Window.Closing
> > event and it didn't help. No luck with wx.Window.Dispose or destructor
> > either. What is the preffered way of postponing the window deletion until
> > I'm finished with my stuff?
>
> What I do in C++
>
> a) Define a new event which the thread sends to the
>    owning frame. Or just notify the window somehow
>    that the thread has ended just so that it doesn't
>    get deleted twice
>
> DEFINE_EVENT_TYPE( wxEVT_THREAD_HAS_ENDED )
>
> b) Here is your wxFrame. Note that the thread
>    will send wxEVT_THREAD_HAS_ENDED either
>    because it simply has finished doing something
>    or after the thread has been stopped by the
>    frame's close handler. In the later case,
>    m_deleteOnExit will be true and the frame
>    will then be destroyed.
>
> IMPLEMENT_CLASS(MyRecallFrame,wxFrame)
>
> BEGIN_EVENT_TABLE(MyRecallFrame,wxFrame)
>     EVT_COMMAND( -1, wxEVT_THREAD_HAS_ENDED,
>                 MyRecallFrame::OnThreadHasEnded )
> END_EVENT_TABLE()
>
> MyRecallFrame::MyRecallFrame( wxWindow *parent, wxWindowID id, const
> wxString &title,
>     const wxPoint &position, const wxSize& size, long style ) :
>     wxFrame( parent, id, title, position, size, style )
> {
>     m_thread = NULL;
>     m_deleteOnThreadExit = false;
>
>     StartThread();
> }
>
> void MyRecallFrame::StartThread()
> {
>     m_thread = new MyRecallThread( this );
>     m_thread->Create();
>     m_thread->Run();
> }
>
> void MyRecallFrame::InterruptThread()
> {
>     if (m_thread)
>         m_thread->Interrupt();
> }
>
> void MyRecallFrame::OnThreadHasEnded( wxCommandEvent &event )
> {
>     m_thread = NULL;
>
>     if (m_deleteOnThreadExit)
>         Destroy();
> }
>
> void MyRecallFrame::OnCloseWindow( wxCloseEvent &event )
> {
>     if (event.CanVeto())
>     {
>         if (m_thread)
>         {
>             m_thread->Interrupt();
>             event.Veto();
>             m_deleteOnThreadExit = true;
>             return;
>         }
>     }
>
>     Destroy();
> }
>
>
>
>
>
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