WindowProc Subclassing
lazarus / 7-LCL

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schu-r · 2006-08-08 11:55

Hi

I Used to Subclass WindowProc for some Controls in Delphi to Write my
own WindowHandler (of course I called the Base Window Handler after
it) just to react on some Windowmessages.

But in Lazarus i cannot change the WindowProc Handler.


Is there a different Way to get to the window Messages of an
individual Control?

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Vincent Snijders · 2006-08-08 12:36

You still can subclass the window procedure, using
Windows.SetWindowLong.

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felipemdc · 2006-08-08 19:21

You can just override the default WindowProc, like this, on your TForm
window:

  TMainWindow = class(TForm)
     ......
  public
{$IFDEF Win32}
    procedure WndProc(var Message : TMessage); override;
{$ENDIF}
  end;

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schu-r · 2006-08-09 12:25

I need to set them at Runtime. Because I look at the Controls of a
Form and then I decide which Controls to subclass. The code Searches
all the Controls and Subclasses them.
This is a kind of LayoutManager similar to Java. It works so far in
Delphi (can change the Look and Feel and even the behaviour of some
Fields).