/// <summary>
/// Called when navigation is performed to a page. You can use this method to load state if it is available.
/// </summary>
/// <param name="e">The <see cref="NavigatedToEventArgs"/> instance containing the event data.</param>
/// <param name="viewModelState">The state of the view model.</param>
public virtual void OnNavigatedTo(NavigatedToEventArgs e, Dictionary <string, object> viewModelState)
{
if (viewModelState != null)
{
RestoreViewModel(viewModelState, this);
}
}
private void OnFrameNavigatedTo(object sender, NavigationEventArgs e)
{
if (_navigatedToEventHandlers.Count > 0)
{
var args = new NavigatedToEventArgs(e);
foreach (var handler in _navigatedToEventHandlers)
{
handler(this, args);
}
}
}
public void OnNavigatedTo_With_RestorableStateAttribute()
{
var viewModelState = new Dictionary<string, object>();
viewModelState.Add("Title", "MyMock");
viewModelState.Add("Description", "MyDescription");
var vm = new MockViewModelWithRestorableStateAttributes();
NavigatedToEventArgs args = new NavigatedToEventArgs();
args.NavigationMode = NavigationMode.Back;
vm.OnNavigatedTo(args, viewModelState);
Assert.AreEqual(vm.Title, viewModelState["Title"]);
Assert.AreEqual(vm.Description, viewModelState["Description"]);
}
public void OnNavigatedTo_With_No_RestorableStateAttributes()
{
var viewModelState = new Dictionary<string, object>();
viewModelState.Add("Title", "MyMock");
viewModelState.Add("Description", "MyDescription");
var viewState = new Dictionary<string, object>();
viewState.Add("Tests.Mocks.MockViewModelWithNoResumableStateAttributes1", viewModelState);
var vm = new MockViewModelWithNoRestorableStateAttributes();
NavigatedToEventArgs args = new NavigatedToEventArgs();
args.NavigationMode = NavigationMode.Back;
vm.OnNavigatedTo(args, viewState);
Assert.IsNull(vm.Title);
Assert.IsNull(vm.Description);
}
public override void OnNavigatedTo(NavigatedToEventArgs e, Dictionary<string, object> viewState)
{
this.OnNavigatedToCommand(e.Parameter, e.NavigationMode, viewState);
}
public void OnNavigatedTo_With_RestorableStateCollection()
{
var childViewModelState = new Dictionary<string, object>();
childViewModelState.Add("Title", "MyChildMock");
childViewModelState.Add("Description", "MyChildDescription");
var viewModelState = new Dictionary<string, object>();
viewModelState.Add("Tests.Mocks.MockViewModelWithResumableStateCollection1", childViewModelState);
var viewState = new Dictionary<string, object>();
viewState.Add("MyEntityId", viewModelState);
var vm = new MockViewModelWithRestorableStateCollection()
{
ChildViewModels = new List<BindableBase>()
{
new MockViewModelWithRestorableStateAttributes
{
Title = "MyChildMock",
Description = "MyChildDescription"
}
}
};
NavigatedToEventArgs args = new NavigatedToEventArgs();
args.NavigationMode = NavigationMode.Back;
vm.OnNavigatedTo(args, viewState);
var childViewModel = (MockViewModelWithRestorableStateAttributes)vm.ChildViewModels.FirstOrDefault();
Assert.AreEqual(childViewModel.Title, childViewModelState["Title"]);
Assert.AreEqual(childViewModel.Description, childViewModelState["Description"]);
}
private void OnFrameNavigatedTo(object sender, NavigationEventArgs e)
{
if (_navigatedToEventHandlers.Count > 0)
{
var args = new NavigatedToEventArgs(e);
foreach (var handler in _navigatedToEventHandlers)
handler(this, args);
}
}
/// <summary>
/// Handles the Navigated event of the Frame control.
/// </summary>
/// <param name="sender">The source of the event.</param>
/// <param name="e">The <see cref="NavigatedToEventArgs"/> instance containing the event data.</param>
private void OnFrameNavigatedTo(object sender, NavigatedToEventArgs e)
{
// Update the page type and parameter of the last navigation
_sessionStateService.SessionState[LastNavigationPageKey] = _frame.Content.GetType().FullName;
_sessionStateService.SessionState[LastNavigationParameterKey] = e.Parameter;
NavigateToCurrentViewModel(e);
}
/// <summary>
/// This method is triggered after navigating to a view model. It is used to load the view model state that was saved previously.
/// </summary>
/// <param name="e">The <see cref="NavigatedToEventArgs"/> instance containing the event data.</param>
private void NavigateToCurrentViewModel(NavigatedToEventArgs e)
{
var frameState = _sessionStateService.GetSessionStateForFrame(_frame);
var viewModelKey = "ViewModel-" + _frame.BackStackDepth;
if (e.NavigationMode == NavigationMode.New)
{
// Clear existing state for forward navigation when adding a new page/view model to the
// navigation stack
var nextViewModelKey = viewModelKey;
int nextViewModelIndex = _frame.BackStackDepth;
while (frameState.Remove(nextViewModelKey))
{
nextViewModelIndex++;
nextViewModelKey = "ViewModel-" + nextViewModelIndex;
}
}
var newView = _frame.Content as FrameworkElement;
if (newView == null) return;
var newViewModel = newView.DataContext as INavigationAware;
if (newViewModel != null)
{
Dictionary<string, object> viewModelState;
if (frameState.ContainsKey(viewModelKey))
{
viewModelState = frameState[viewModelKey] as Dictionary<string, object>;
}
else
{
viewModelState = new Dictionary<string, object>();
}
newViewModel.OnNavigatedTo(e, viewModelState);
frameState[viewModelKey] = viewModelState;
}
}
