Managed C++/CLI

Form::WndProc(m);

public class extendedDateTimePicker : DateTimePicker {
    protected override void  WndProc(ref Message m) {
         base.WndProc(ref m);
    }
}

Luc Pattyn wrote:

the message parameter takes a reference.

public ref class extendedDateTimePicker : DateTimePicker
{
protected:
	[SecurityPermission(SecurityAction::Demand, Flags=SecurityPermissionFlag::UnmanagedCode)]
	virtual void WndProc( Message% m ) override
	{	
		if ( m.Msg == (int) 0x0014 ) {	//WM_ERASEBKGND
                     // your code				
		}
		DateTimePicker::WndProc(m);
	}
};

LetsMond wrote:

how do I inform the main GUI thread that the worker thread has finished (the data is ready) so that it can update the GUI

MethodInvoker^ method = gcnew MethodInvoker(this, &YourForm::UpdateUI);
this->BeginInvoke(method);

LetsMond wrote:

The only method I know (used back before Managed C++/CLI) is to send a windows message from the worker thread. This is handled in the message loop of the main GUI thread and so the GUI can be updated.

SynchronizationContext^ context = SynchronizationContext::Current;
Thread^ t = gcnew Thread(gcnew ParameterizedThreadStart(this, &YourForm::Execute));
t->Start(context);

void Execute(Object^ obj)
{
    SynchronizationContext^ context = dynamic_cast<SynchronizationContext^>(obj);
    context->Post(gcnew SendOrPostCallback(this, &YourForm::UpdateUI), "Sample text");
}

void UpdateUI(Object^ obj)
{
   // your UI update code
}

LetsMond wrote:

However this feels a bit clunky to me and can cause problems when a dialog is open and the windows message is handled in the dialog's message loop and not that of the main application.

dybs wrote:

I believe the WorkerCompleted event executes on the thread that started the worker thread

LetsMond wrote:

My WorkerComplete event is not always being called from the main GUI thread