/// <summary>
/// Overrides the window's OnClosing method and calls the Viewmodel's
/// <see cref="MVVMbasics.Viewmodels.BaseViewmodel.CancelNavigatingFrom">CancelNavigatingFrom</see> method,
/// allowing the actual (derived) window class to cancel the unload operation.
/// </summary>
/// <param name="e"></param>
protected override void OnClosing(System.ComponentModel.CancelEventArgs e)
{
InstantiateViewmodel();
if (Viewmodel != null)
{
e.Cancel = Viewmodel.CancelNavigatingFrom(ViewState.Closed);
}
base.OnClosing(e);
}
/// <summary>
/// Overrides the page's OnNavigatingFrom method and calls the Viewmodel's
/// <see cref="MVVMbasics.Viewmodels.BaseViewmodel.CancelNavigatingFrom">CancelNavigatingFrom</see> method,
/// allowing the actual (derived) window class to cancel the navigation.
/// </summary>
/// <param name="e"></param>
protected override void OnNavigatingFrom(NavigatingCancelEventArgs e)
{
InstantiateViewmodel();
if (Viewmodel != null)
{
ViewState viewState;
if (e.NavigationMode == NavigationMode.Back || IsMvvmBasicsBackNavigation())
{
viewState = ViewState.Closed;
// If parameters for the backward navigation have been stored, pass them on to the previous page!
if (BackParameters != null)
{
if (BackParameters.Count > 0)
{
var application = Application.Current as BaseApplication;
if (application != null)
{
Frame frame = application.RootFrame;
if (frame != null)
{
frame.Navigated += (sender, args) =>
{
var previousView = args.Content as BaseView;
if (previousView != null)
{
previousView.Parameters = BackParameters;
}
};
}
}
}
}
}
else
{
viewState = ViewState.Deactivated; // switching to another page inside the App
if (NavigatorServiceReference != null)
{
// Store the current Viewmodel's instance on the back stack
NavigatorServiceReference.AddToBackstack(Viewmodel);
}
}
e.Cancel = Viewmodel.CancelNavigatingFrom(viewState);
}
base.OnNavigatingFrom(e);
}