WPF showing dialog before main window

Question

How one can show dialog window (e.g. login / options etc.) before the main window?

Here is what I tried (it apparently has once worked, but not anymore):

Answer 1

So you want to show one window, then another, but close down the app when that window is closed? You may need to set the ShutdownMode to OnMainWindowClose and set the MainWindow to Window1, along the lines ok:

Window1 myMainWindow = new Window1();
Application.Current.ShutdownMode = ShutdownMode.OnMainWindowClose;
Application.Current.MainWindow = myMainWindow;
DialogWindow myDialogWindow = new DialogWindow();
myDialogWindow.ShowDialog();