/// <summary>
/// Invoked when this page is about to be displayed in a Frame.
/// This method calls <see cref="LoadState"/>, where all page specific
/// navigation and process lifetime management logic should be placed.
/// </summary>
/// <param name="e">Event data that describes how this page was reached. The Parameter
/// property provides the group to be displayed.</param>
public void OnNavigatedTo(NavigationEventArgs e)
{
var frameState = SuspensionHelper.SessionStateForFrame(this.Frame);
this._pageKey = "Page-" + this.Frame.BackStackDepth;
if (e.NavigationMode == NavigationMode.New)
{
// Clear existing state for forward navigation when adding a new page to the
// navigation stack
var nextPageKey = this._pageKey;
int nextPageIndex = this.Frame.BackStackDepth;
while (frameState.Remove(nextPageKey))
{
nextPageIndex++;
nextPageKey = "Page-" + nextPageIndex;
}
// Pass the navigation parameter to the new page
if (this.LoadState != null)
{
this.LoadState(this, new LoadStateEventArgs(e.Parameter, null));
}
}
else
{
// Pass the navigation parameter and preserved page state to the page, using
// the same strategy for loading suspended state and recreating pages discarded
// from cache
if (this.LoadState != null)
{
this.LoadState(this, new LoadStateEventArgs(e.Parameter, (Dictionary <String, Object>)frameState[this._pageKey]));
}
}
}
/// <summary>
/// Invoked when this page will no longer be displayed in a Frame.
/// This method calls <see cref="SaveState"/>, where all page specific
/// navigation and process lifetime management logic should be placed.
/// </summary>
/// <param name="e">Event data that describes how this page was reached. The Parameter
/// property provides the group to be displayed.</param>
public void OnNavigatedFrom(NavigationEventArgs e)
{
var frameState = SuspensionHelper.SessionStateForFrame(this.Frame);
var pageState = new Dictionary <String, Object>();
if (this.SaveState != null)
{
this.SaveState(this, new SaveStateEventArgs(pageState));
}
frameState[_pageKey] = pageState;
}