Close Delphi dialog after [x] seconds

Question

Is it possible to get Delphi to close a ShowMessage or MessageDlg Dialog after a certain length of time?

I want to show a message to the user when the application is shut down, but do not want to stop the application from shutting down for more than 10 seconds or so.

Can I get the default dialog to close after a defined time, or will I need to write my own form?

Answer 1

Your application is actually still working while a modal dialog or system message box or similar is active (or while a menu is open), it's just that a secondary message loop is running which processes all messages - all messages sent or posted to it, and it will synthesize (and process) WM_TIMER and WM_PAINT messages when necessary as well.

So there's no need to create a thread or jump through any other hoops, you simply need to schedule the code that closes the message box to be run after those 10 seconds have elapsed. A simple way to do that is to call SetTimer() without a target HWND, but a callback function:

procedure CloseMessageBox(AWnd: HWND; AMsg: UINT; AIDEvent: UINT_PTR;
  ATicks: DWORD); stdcall;
var
  Wnd: HWND;
begin
  KillTimer(AWnd, AIDEvent);
  // active window of the calling thread should be the message box
  Wnd := GetActiveWindow;
  if IsWindow(Wnd) then
    PostMessage(Wnd, WM_CLOSE, 0, 0);
end;

procedure TForm1.Button1Click(Sender: TObject);
var
  TimerId: UINT_PTR;
begin
  TimerId := SetTimer(0, 0, 10 * 1000, @CloseMessageBox);
  Application.MessageBox('Will auto-close after 10 seconds...', nil);
  // prevent timer callback if user already closed the message box
  KillTimer(0, TimerId);
end;

Error handling ommitted, but this should get you started.

Answer 2

You can try to do it with a standard Message dialog. Create the dialog with CreateMessageDialog procedure from Dialogs and after add the controls that you need.

In a form with a TButton define onClick with this:

procedure TForm1.Button1Click(Sender: TObject);
var
  tim:TTimer;
begin
  // create the message
  AMsgDialog := CreateMessageDialog('This is a test message.',mtWarning, [mbYes, mbNo]) ;
  lbl := TLabel.Create(AMsgDialog) ;
  tim := TTimer.Create(AMsgDialog);
  counter := 0;

  // Define and adding components
  with AMsgDialog do
   try
    Caption := 'Dialog Title' ;
    Height := 169;

    // Label
    lbl.Parent := AMsgDialog;
    lbl.Caption := 'Counting...';
    lbl.Top := 121;
    lbl.Left := 8;

    // Timer
    tim.Interval := 400;
    tim.OnTimer := myOnTimer;
    tim.Enabled := true;

    // result of Dialog
    if (ShowModal = ID_YES) then begin
      Button1.Caption := 'Press YES';
    end
    else begin
      Button1.Caption := 'Press NO';
    end;
   finally
    Free;
   end;
end;

An the OnTimer property like this:

procedure TForm1.MyOnTimer(Sender: TObject);
begin

  inc(counter);
  lbl.Caption := 'Counting: ' + IntToStr(counter);
  if (counter >= 5) then begin
    AMsgDialog.Close;
  end;
end;

Define the variables and procedure:

  TForm1 = class(TForm)
    Button1: TButton;
    procedure Button1Click(Sender: TObject);
  private
    AMsgDialog: TForm;
    lbl:TLabel;
    counter:integer;
    procedure MyOnTimer(Sender: TObject);
  end;

And test it.
The form close automatically when the timer final the CountDown. Similar this you can add other type of components.

Regards.