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How to handle parental messages

Now when one expert answered my question about hooking parental messages, I need help again. I need to handle and MODIFY a result of WM_NCHITTEST message. And I need to do this from hook. The idea was: user places component onto the form and the component takes the form's WM_NCHITTEST do decide what's caption, what's resizable border etc...

rwilson032697

Here's an example os using NCHITTEST to drag a form by clicking any where in it. It fools windows into thinking the caption has been clicked on.

This should show you all you need...

Cheers,

Raymond.

unit Unit1;

interface

uses
Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs;

type
TForm1 = class(TForm)
private
{ Private declarations }
public
{ Public declarations }
procedure WMNCHitTest(var M: TWMNCHitTest); message WM_NCHITTEST;
end;

var
Form1: TForm1;

implementation

{$R *.DFM}

procedure TForm1.WMNCHitTest(var M: TWMNCHitTest);
begin
inherited;
{If the client has been clicked, make Windows believe}
{it was the caption bar that was clicked on}
if M.Result = htClient then
M.Result := htCaption;
end;

end.

inthe

listening..

rpo

I think it's easier to do what you want using subclassing instead of hooks.

I would do this with SetWindowLong with GWL_WNDPROC parameter.

You steel need that MakeHookInstance function to get an address for new window procedure :)

Roman.

Aleq

ASKER

rwilson: I know this solution, but I need to handle WM_NCHITTEST from component placed on that form.

Jaymol

Can I just ask, so I get it straight in my head.....are you saying you wish to write a component that handles the form's windows messages? If so, I've got code for that. Let me know.

John.

rwilson032697

Aleq: The point is that you do just the same thing in your component (the handling of the message, that is).

Cheers,
Raymond.

Aleq

ASKER

rwilson - I tried it. Handling WM_NCHITTEST in component was very interesting - it allowed me to resize the component itself, not parental form .....

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rpo

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Aleq

ASKER

Can you give me the whole TEnhancedForm ? I've tried this code, but It made some problems....