private async void App_OnBackRequested(object sender, BackRequestedEventArgs e)
{
e.Handled = true;
if (IsDirty)
{
MessageDialog messageDialog = MessageDialogHelper.CreateDialogForConfirmOnExit();
var result = await messageDialog.ShowAsync();
if (result.Label.Equals("Yes") && NavigationHelper.CanGoBack())
{
NavigationHelper.GoBack();
IsDirty = false;
}
}
else
{
if (NavigationHelper.CanGoBack())
{
NavigationHelper.GoBack();
e.Handled = true;
}
}
}