private void ContentLoader_BeginLoad_Callback(IAsyncResult result)
{
DependencyObject content = null;
Uri uriBeingLoaded = null;
try
{
NavigationOperation asyncNavigationOperationCompleted = result.AsyncState as NavigationOperation;
NavigationOperation navOp = this._currentNavigation;
if (navOp == null || navOp.Uri != asyncNavigationOperationCompleted.Uri)
{
// We already fired NavigationStopped in NavigateCore(), so just return without doing anything
return;
}
uriBeingLoaded = navOp.UriBeforeMapping;
content = this._contentLoader.EndLoad(result) as DependencyObject;
// If the content is anything but a UserControl, we should throw.
// We support UserControls as they are a typical thing created in designers such as Blend,
// but for a full experience one would use Page to get to things like NavigationContext,
// NavigationService, Title, etc.
if (!(content is UserControl))
{
throw new InvalidOperationException(string.Format(CultureInfo.InvariantCulture,
Resource.NavigationService_ContentIsNotAUserControl,
content == null ? "null" : content.GetType().ToString(),
"System.Windows.Controls.UserControl"));
}
// Content loader was successful, so complete navigation
// Create a new navigation context
JournalEntry.SetNavigationContext(content, new NavigationContext(UriParsingHelper.InternalUriParseQueryStringToDictionary(asyncNavigationOperationCompleted.Uri, true /* decodeResults */)));
content.SetValue(NavigationServiceProperty, this);
// Complete navigation operation
this.CompleteNavigation(content);
}
catch (Exception ex)
{
if (this.RaiseNavigationFailed(uriBeingLoaded, ex))
{
throw;
}
}
}
