/// <summary>
/// Overrides the page's OnNavigatedFrom method and calls the Viewmodel's
/// <see cref="MVVMbasics.Viewmodels.BaseViewmodel.OnNavigatedFrom">OnNavigatedFrom</see> method.
/// </summary>
/// <param name="e"></param>
protected override void OnNavigatedFrom(NavigationEventArgs e)
{
InstantiateViewmodel();
if (Viewmodel != null)
{
ViewState viewState;
if (e.NavigationMode == NavigationMode.Back || IsMvvmBasicsBackNavigation())
{
viewState = ViewState.Closed; // switching to the previous page inside the App
}
else
{
viewState = ViewState.Deactivated; // switching to another page inside the App
}
Viewmodel.OnNavigatedFrom(viewState);
}
// Ensure that the page can correctly be disposed
DataContextChanged -= View_DataContextChanged;
Viewmodel = null;
DataContext = null;
Window.Current.VisibilityChanged -= OnWindowVisibilityChanged;
base.OnNavigatedFrom(e);
}
/// <summary>
/// Overrides the window's OnClosed method and calls the Viewmodel's
/// <see cref="MVVMbasics.Viewmodels.BaseViewmodel.OnNavigatedFrom">OnNavigatedFrom</see> method.
/// </summary>
/// <param name="e"></param>
protected override void OnClosed(System.EventArgs e)
{
InstantiateViewmodel();
if (Viewmodel != null)
{
Viewmodel.OnNavigatedFrom(ViewState.Closed);
}
base.OnClosed(e);
}
/// <summary>
/// Retrieves a View and navigates to the corresponding window.
/// </summary>
public void NavigateTo <T>(ParameterList parameters) where T : BaseViewmodel
{
if (_mappings.ContainsKey(typeof(T)))
{
// If the currently active Viewmodel is registered in the Application class, call the OnNavigatedFrom
// event on this Viewmodel!
var application = Application.Current as BaseApplication;
if (application != null)
{
BaseViewmodel currentViewmodel = application.CurrentViewmodel;
if (currentViewmodel != null)
{
currentViewmodel.OnNavigatedFrom(ViewState.Deactivated);
}
}
// Now actually instantiate and open the new window
BaseView window = (BaseView)Activator.CreateInstance(_mappings[typeof(T)]);
_windowStack.Add(window);
window.Initialize(parameters);
window.ShowDialog(); // Returns only after the new window has been closed
// After the new window has been closed (either through NavigateBack or through the X button), pass
// parameters to the previous window (since this is the window that will be reactivated)
if (_windowStack.Count > 1)
{
var previousWindow = _windowStack[_windowStack.Count - 2] as BaseView;
if (previousWindow != null)
{
previousWindow.Initialize(_backParameters);
_backParameters = new ParameterList();
}
}
else
{
if (Application.Current != null) // For non-WPF-applications, this is NULL and the App's main window
// can therefore not be retrieved
// (due to this, passing back parameters will not work in those
// Applications)
{
// If no previous window is found on the back stack, the App's main window is our target:
var previousWindow = Application.Current.MainWindow as BaseView;
if (previousWindow != null)
{
previousWindow.Initialize(_backParameters);
_backParameters = new ParameterList();
}
}
}
// Finally remove the closing window from the back stack:
if (_windowStack.Count > 0)
{
_windowStack.RemoveAt(_windowStack.Count - 1);
}
}
}
protected override void OnDisappearing()
{
InstantiateViewmodel();
if (Viewmodel != null)
{
MVVMbasics.Services.ViewState viewState;
if (IsMvvmBasicsBackNavigation())
{
viewState = MVVMbasics.Services.ViewState.Closed; // switching to the previous page inside the App
}
else
{
viewState = MVVMbasics.Services.ViewState.Deactivated; // switching to another page inside the App
}
Viewmodel.OnNavigatedFrom(viewState);
}
base.OnDisappearing();
}