protected void NavigationHelperSaveState(object sender, SaveStateEventArgs e)
{
if (e.PageState == null)
{
throw new InvalidOperationException("PageState is null");
}
if (e.PageState.ContainsKey(StateKey))
{
e.PageState.Remove(StateKey);
}
var state = SaveState();
if (state != null)
{
e.PageState.Add(StateKey, state);
}
}
/// <summary>
/// Preserves state associated with this page in case the application is suspended or the
/// page is discarded from the navigation cache. Values must conform to the serialization
/// requirements of <see cref="SuspensionManager.SessionState"/>.
/// </summary>
/// <param name="sender">The source of the event; typically <see cref="NavigationHelper"/></param>
/// <param name="e">Event data that provides an empty dictionary to be populated with
/// serializable state.</param>
private void navigationHelper_SaveState(object sender, SaveStateEventArgs e)
{
}