public static T TryFindAncestorOrSelf <T>([NotNull] this DependencyObject self, [NotNull] Func <T, bool> match)
{
Contract.Requires(self != null);
Contract.Requires(match != null);
return(self.AncestorsAndSelf().OfType <T>().FirstOrDefault(match));
}
public static IEnumerable <DependencyObject> Ancestors([NotNull] this DependencyObject self)
{
Contract.Requires(self != null);
Contract.Ensures(Contract.Result <IEnumerable <DependencyObject> >() != null);
return(self.AncestorsAndSelf().Skip(1));
}
private static RouterService WalkAncestorsForRouterService(DependencyObject dependencyObject)
{
var routerService = from ancestor in dependencyObject.AncestorsAndSelf()
let service = RoutingComponent.GetRouterService(ancestor)
where service != null
select service;
return(routerService.LastOrDefault());
}
/// <summary>
/// Determines whether the routed event args should be handled.
/// </summary>
/// <param name="args"></param>
/// <returns></returns>
/// <remarks>This method prevents parent frames from handling routed commands.</remarks>
private bool HandleRoutedEvent(CanExecuteRoutedEventArgs args)
{
DependencyObject originalSource = args.OriginalSource as DependencyObject;
if (originalSource == null)
{
return(false);
}
return(originalSource.AncestorsAndSelf().OfType <ModernFrame>().FirstOrDefault() == this);
}
/// <summary>
/// When overridden in a derived class, returns a <see cref="T:System.Windows.DataTemplate" /> based on custom logic.
/// </summary>
/// <param name="item">The data object for which to select the template.</param>
/// <param name="container">The data-bound object.</param>
/// <returns>
/// Returns a <see cref="T:System.Windows.DataTemplate" /> or null. The default value is null.
/// </returns>
public override DataTemplate SelectTemplate(object item, [CanBeNull] DependencyObject container)
{
if ((item == null) || (container == null))
{
return(null);
}
var frameworkElement = container.AncestorsAndSelf().OfType <FrameworkElement>().FirstOrDefault();
if (frameworkElement == null)
{
return(null);
}
var key = DataTemplateManager.CreateKey(item.GetType(), Role);
return((frameworkElement.TryFindResource(key) as DataTemplate) ?? FallbackValue);
}
/// <summary>
/// Returns a collection containing this element and all ancestor elements
/// which match the given type.
/// </summary>
public static IEnumerable <DependencyObject> AncestorsAndSelf <T>(this DependencyObject item)
{
return(item.AncestorsAndSelf().Where(i => i is T).Cast <DependencyObject>());
}
/// <summary>
/// Gets the message to show when an export provider could not be located in the visual tree.
/// </summary>
/// <param name="obj">The object.</param>
/// <returns>The message.</returns>
public static string GetMissingExportProviderMessage(this DependencyObject obj)
{
return("Export provider must be registered in the visual tree " + string.Join("/", obj.AncestorsAndSelf().Reverse().Select(o => o?.GetType().Name)));
}
/// <summary>
/// Returns a collection containing this element and all ancestor elements
/// which match the given type.
/// </summary>
public static IEnumerable <T> AncestorsAndSelf <T>(this DependencyObject item)
{
return(item.AncestorsAndSelf().OfType <T>());
}
public static T TryFindAncestorOrSelf <T>([NotNull] this DependencyObject self, [NotNull] Func <T, bool> match)
{
return(self.AncestorsAndSelf().OfType <T>().FirstOrDefault(match));
}
public static T TryFindAncestorOrSelf <T>([NotNull] this DependencyObject self)
{
return(self.AncestorsAndSelf().OfType <T>().FirstOrDefault());
}
public static IEnumerable <DependencyObject> Ancestors([NotNull] this DependencyObject self)
{
return(self.AncestorsAndSelf().Skip(1));
}
internal static string GetMissingExportProviderMessage([NotNull] this DependencyObject obj)
{
Contract.Requires(obj != null);
Contract.Ensures(Contract.Result <string>() != null);
return("Export provider must be registered in the visual tree " + string.Join("/", obj.AncestorsAndSelf().Reverse().Select(o => o?.GetType().Name)));
}
