/// <summary>
/// Tells whether or not the target Uri can be loaded
/// </summary>
/// <param name="targetUri">A URI to load</param>
/// <param name="currentUri">The current URI</param>
/// <returns>True if the targetURI can be loaded</returns>
public bool CanLoad(Uri targetUri, Uri currentUri)
{
return(UriParsingHelper.InternalUriIsNavigable(targetUri));
}
private bool NavigateCore(Uri uri, NavigationMode mode, bool suppressJournalAdd)
{
try
{
if (uri == null)
{
throw new ArgumentNullException("uri", Resource.NavigationService_NavigationToANullUriIsNotSupported);
}
// Make sure we're on the UI thread because of the DependencyProperties we use.
if (!this.Host.Dispatcher.CheckAccess())
{
// Move to UI thread
this.Host.Dispatcher.BeginInvoke(() => this.NavigateCore(uri, mode, suppressJournalAdd));
return(true);
}
Uri mappedUri = uri;
// If the Uri is only a fragment, mapping does not take place
if (!UriParsingHelper.InternalUriIsFragment(uri))
{
UriMapperBase mapper = this.Host.UriMapper;
if (mapper != null)
{
Uri uriFromMapper = mapper.MapUri(uri);
if (uriFromMapper != null && !String.IsNullOrEmpty(uriFromMapper.OriginalString))
{
mappedUri = uriFromMapper;
}
else
{
mappedUri = uri;
}
}
}
Uri mergedUriAfterMapping = UriParsingHelper.InternalUriMerge(this._currentSourceAfterMapping, mappedUri) ?? mappedUri;
Uri mergedUri = UriParsingHelper.InternalUriMerge(this._currentSource, uri) ?? uri;
// If we're navigating to just a fragment (i.e. "#frag1") or to a page which differs only in the fragment
// (i.e. "Page.xaml?id=123" to "Page.xaml?id=123#frag1") then complete navigation without involving the content loader
bool isFragmentNavigationOnly = UriParsingHelper.InternalUriIsFragment(mappedUri) ||
UriParsingHelper.InternalUriGetAllButFragment(mergedUri) == UriParsingHelper.InternalUriGetAllButFragment(this._currentSource);
// Check to see if anyone wants to cancel
if (mode == NavigationMode.New)
{
if (this.RaiseNavigating(mergedUri, mode, isFragmentNavigationOnly) == true)
{
// Someone stopped us
this.RaiseNavigationStopped(null, mergedUri);
return(true);
}
}
if (!UriParsingHelper.InternalUriIsNavigable(mappedUri))
{
throw new ArgumentException(Resource.NavigationService_UriNotNavigable, "uri");
}
if (isFragmentNavigationOnly && this.Host.Content == null)
{
// It doesn't make sense to fragment navigate when there's no content, so raise NavigationFailed
throw new InvalidOperationException(string.Format(CultureInfo.InvariantCulture,
Resource.NavigationService_FragmentNavigationRequiresContent,
"Frame"));
}
// Stop in-progress navigation
this.StopLoading();
return(this.NavigateCore_StartNavigation(uri, mode, suppressJournalAdd, mergedUriAfterMapping, mergedUri, isFragmentNavigationOnly));
}
catch (Exception ex)
{
if (this.RaiseNavigationFailed(uri, ex))
{
throw;
}
return(true);
}
}
