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Asked: 2026-05-18T08:31:29+00:00

I’m using a 3rd party library that uses a lot of threads. I’ve just

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I’m using a 3rd party library that uses a lot of threads.

I’ve just started using messages to communicate back to the main thread from a thread. It’s all working, but using SendMessage the way I describe below seems cumbersome because the main form has to dispatch all the messages. Is there a way to send a message directly to a frame or object, without depending on the main form?

At program startup:

 MyMessageNumber1 :=  RegisterWindowMessage('MyUniqueID1');
 MyMessageNumber2 :=  RegisterWindowMessage('MyUniqueID2');

When sending a message without any data, I do:

 SendMessage(Application.MainForm.Handle,  MyMessageNumber1)

My main form has this:

procedure WndProc(var Message: TMessage); override;
if (Message.Msg = MyMessageNumber1)
  ... call a frame or other object's method that handles this particular message
else if (Message.Msg = MyMessageNumber2) then
  ... call another ....
else
  inherited;

In summary: the above WndProc has to know far more than I’d prefer about all the messages and who to dispatch them to.

How can I send a message directly from a thread in a way that any object can receive it?

All of these messages have no data associated with them. (We’ll get to that some other day!) 🙂

TIA

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1 Answer

  1. Editorial Team

    Other forms and frames have handles as well, and you can define message-handling methods on them, then post the message directly to the form or frame. (Or control, for that matter, if you’re building your own custom controls.)

    See http://docwiki.embarcadero.com/RADStudio/en/Declaring_a_New_Message-handling_Method for an overview on setting up message-handling methods.

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