/// <summary>
/// This method will be called when navigating away from a page. You can use this method to save your view model data in case of a suspension event.
/// </summary>
/// <param name="e">The <see cref="NavigatingFromEventArgs"/> instance containing the event data.</param>
/// <param name="viewModelState">The state of the view model.</param>
/// <param name="suspending">if set to <c>true</c> you are navigating away from this viewmodel due to a suspension event.</param>
public virtual void OnNavigatingFrom(NavigatingFromEventArgs e, Dictionary <string, object> viewModelState, bool suspending)
{
if (viewModelState != null)
{
FillStateDictionary(viewModelState, this);
}
}
private void OnFrameNavigatingFrom(object sender, NavigatingCancelEventArgs e)
{
if (_navigatingFromEventHandlers.Count > 0)
{
var args = new NavigatingFromEventArgs(e);
foreach (var handler in _navigatingFromEventHandlers)
{
handler(this, args);
}
}
}
public void OnNavigatedFrom_With_No_RestorableStateAttributes()
{
var vm = new MockViewModelWithNoRestorableStateAttributes()
{
Title = "MyMock",
Description = "MyDescription",
};
var result = new Dictionary<string, object>();
NavigatingFromEventArgs args = new NavigatingFromEventArgs();
vm.OnNavigatingFrom(args, result, true);
Assert.IsTrue(result.Keys.Count == 0);
}
public override void OnNavigatingFrom(NavigatingFromEventArgs e, Dictionary<string, object> viewState, bool suspending)
{
this.OnNavigatedFromCommand(viewState, suspending);
}
public override void OnNavigatingFrom(NavigatingFromEventArgs e, Dictionary<string, object> viewModelState, bool suspending)
{
e.Cancel = _isNavigationDisabled;
base.OnNavigatingFrom(e, viewModelState, suspending);
}
private void OnFrameNavigatingFrom(object sender, NavigatingCancelEventArgs e)
{
if (_navigatingFromEventHandlers.Count > 0)
{
var args = new NavigatingFromEventArgs(e);
foreach (var handler in _navigatingFromEventHandlers)
handler(this, args);
}
}
/// <summary>
/// Handles the Navigating event of the Frame control.
/// </summary>
/// <param name="sender">The source of the event.</param>
/// <param name="e">The <see cref="NavigatingFromEventArgs"/> instance containing the event data.</param>
private void OnFrameNavigatingFrom(object sender, NavigatingFromEventArgs e)
{
NavigateFromCurrentViewModel(e, false);
}
/// <summary>
/// Navigates away from the current viewmodel.
/// </summary>
/// <param name="e">The <see cref="NavigatingFromEventArgs"/> instance containing the event data.</param>
/// <param name="suspending">True if it is navigating away from the viewmodel due to a suspend event.</param>
private void NavigateFromCurrentViewModel(NavigatingFromEventArgs e, bool suspending)
{
var departingView = _frame.Content as FrameworkElement;
if (departingView == null) return;
var frameState = _sessionStateService.GetSessionStateForFrame(_frame);
var departingViewModel = departingView.DataContext as INavigationAware;
var viewModelKey = "ViewModel-" + _frame.BackStackDepth;
if (departingViewModel != null)
{
var viewModelState = frameState.ContainsKey(viewModelKey)
? frameState[viewModelKey] as Dictionary<string, object>
: null;
departingViewModel.OnNavigatingFrom(e, viewModelState, suspending);
}
}
