public string OnBeforeUnload()
{
// Setup initial conditions.
if (WindowClosing == null) return null;
// Check with event-listeners to see if any of them want to cancel the window-close operation.
var args = new HtmlWindowCloseEventArgs();
OnWindowClosing(this, args);
if (!args.Cancel) return null; // No one wanted to stop the window from closing.
// Present the 'Are you sure' dialog to the use (via the browser).
var message = args.DialogMessage.AsNullWhenEmpty() != null
? args.DialogMessage
: DefaultDialogMessage;
return message;
}
private void DontCancelOnClose(object sender, HtmlWindowCloseEventArgs e)
{
Debug.WriteLine("!! Event: WindowClosing (Non-Cancel Handler)");
e.Cancel = false;
}
private static void OnWindowClosing(object sender, HtmlWindowCloseEventArgs e) { if (WindowClosing != null) WindowClosing(sender, e); }
private void CancelOnClose(object sender, HtmlWindowCloseEventArgs e)
{
Debug.WriteLine("!! Event: WindowClosing (Cancel Handler)");
e.DialogMessage = GetMessage();
e.Cancel = true;
}
