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?
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.
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.
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