[DUG] selective processing of Windows messages

[Karl at Work]

> Does anyone know of a component or some easy way to
> selectively process
> the Windows message queue for the application.  For instance
> I may want
> a specific message to be processed but nothing else, or I may
> want all
> messages destined for a specific thread.
>
> For example, Application.ProcessMessages(Handle, WM_USER) would be
> perfect.

PeekMessage searches the message queue, eg. (untried)

procedure ProcessMessagesOfType(AHandle: HWND; AMessage: UINT);
var LMsg: TMsg;
begin
  while PeekMessage(LMsg, AHandle, AMessage, AMessage, PM_REMOVE) do
  begin
    TranslateMessage(LMsg);
    DispatchMessage(LMsg);
  end;
end;

Having said that, I'm curious to know why you want to process the message
queue out of order.  I suggest that there's probably a way to get what you
want without having to do that.  Maybe you could give us a bit more info
about what you're trying to achieve?

Other functions that might help:
PostThreadMessage targets a message to a particular thread
RegisterWindowMessage is useful to avoid WM_USER+X broadcast conflicts
between forms/apps

Cheers,
Carl