Question and Answer Database
FAQ1025D.txt Subclass the window procedure for a TForm
Category :VCL
Platform :All
Product :All 32 bit
Question:
How can I subclass the window procedure for a TForm?
Answer:
Override the WinProc procedure for the form. The following example
overrides the window procedure for the form, and responds to the
WM_CANCELMODE message, indicating that a messagebox or other dialog
box has been executed.
Example:
type
TForm1 = class(TForm)
Button1: TButton;
procedure WndProc (var Message: TMessage); override;
procedure Button1Click(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
end;
var
Form1: TForm1;
implementation
{$R *.DFM}
procedure TForm1.WndProc (var Message: TMessage);
begin
if Message.Msg = WM_CANCELMODE then begin
Form1.Caption := 'A dialog or message box has popped up';
end else
inherited
end;
procedure TForm1.Button1Click(Sender: TObject);
begin
ShowMessage('Test Message');
end;
7/16/98 4:31:28 PM
Last Modified: 01-SEP-99