Event when all mdi forms are closed

Question

Guys, I'd like if anyone knows any event or method that I can intercept when all MDI forms were closed.

Example:

I want to implement an event in my main form where when I close all MDI forms, such an event was triggered.

Grateful if anyone can help.

Answer 1

MDI child forms (in fact any form), while being destroyed, will notify the main form. You can use this notification mechanism. Example:

type
  TForm1 = class(TForm)
    ..
  protected
    procedure Notification(AComponent: TComponent; Operation: TOperation);
      override;

  ..

procedure TForm1.Notification(AComponent: TComponent; Operation: TOperation);
begin
  inherited;
  if (Operation = opRemove) and (AComponent is TForm) and
      (TForm(AComponent).FormStyle = fsMDIChild) and
      (MDIChildCount = 0) then begin

    // do work

  end;
end;