When the DeleteEvent is called by a Gtk# window, how can I prevent the window from closing?

Question

When the window closes, the user is asked to save the file that they edited. They should also have an option to cancel quitting the application. In WPF I can set the CancelEventArgs.Cancel property to true to do this. Is there an equivalent/workaround in Gtk#?

Accepted Answer

You need to set the DeleteEventArgs.RetVal to true, not false. From the relevant Mono documentation:

To keep a `Gtk.Window` from closing, set `Gtk.DeleteEventHandler`'s `Gtk.DeleteEventArgs.RetVal` to `true`.

When the DeleteEvent is called by a Gtk# window, how can I prevent the window from closing?

Solution

Problem