How can I mark the default value of a custom dependency property to be false?
Here is an example : [C#] public class MyStateControl : ButtonBase { public MyStateControl() : base() { } public Boolean State { get { return (Boolean)this.GetValue(StateProperty); } set { this.SetValue(StateProperty, value); } } public static readonly DependencyProperty StateProperty = DependencyProperty.Register( ‘State’, typeof(Boolean), typeof(MyStateControl),new PropertyMetadata(false)); }
How can I create Custom Read-Only Dependency Properties ?
The typical reason for specifying a read-only dependency property is that these are the properties that is used to determine the state, but where the state is defined in a multitude of factors. A typical example for a read-only property is IsMouseHover This example shows how to ’register’ an attached property as read-only. You can use dependency properties on any ’DependencyObject’ types. [C#] public static readonly DependencyProperty IsBubbleSourceProperty = DependencyProperty.RegisterReadOnly( ‘IsBubbleSource’, typeof(Boolean), typeof(AquariumObject), new FrameworkPropertyMetadata(false, FrameworkPropertyMetadataOptions.AffectsRender) );
How can I enumerate all the descendants of a visual object ?
You can enumerate all the descendants of a visual object as follows : [C#] // Enumerate all the descendants of the visual object. static public void EnumVisual(Visual myVisual) { for (int i = 0; i < VisualTreeHelper.GetChildrenCount(myVisual); i++) { // Retrieve child visual at specified index value. Visual childVisual = (Visual)VisualTreeHelper.GetChild(myVisual, i); // Do processing of the child visual object. // Enumerate children of the child visual object. EnumVisual(childVisual); } }
How do I see the templates used by the WPF framework controls?
Here is a very good tool put togather by Chris Sells and Ian Griffiths that shows the templates corresponding to each control in the Presentation Framework dll: ShowMeTheTemplate
I have a sequence of animations I want to execute one after another, how do I do that?
Note that in WPF all animations (element.BeginAnimation method) are executed asynchronously. So, if you call a bunch of BeginAnimation methods one after another in a for loop, they all will overlap and not really execute one after another. There is really no way to chain animations in WPF. You will have to basically listen to an animation’s Completed event and then trigger the next animation. To make such code efficient and scalable I came up with this recursion with in-line event handler based approach: Let us say you want to increase the width of these 2 rectangles one after the other via animation: [XAML] <Canvas> <Rectangle x:Name=’rect1′ Canvas.Top=’0′ Width=’30’ Height=’30’ Fill=’Aqua’></Rectangle> <Rectangle x:Name=’rect2′ Canvas.Top=’50’ Width=’30’ Height=’30’ Fill=’Azure’></Rectangle> </Canvas> The code-behind for this would be: [C#] private void Window_Loaded(object sender, RoutedEventArgs e) { DoubleAnimation da = new DoubleAnimation(100, new Duration(TimeSpan.FromSeconds(3))); List list = new List(); list.Add(new object[] { rect1, Rectangle.WidthProperty, da}); list.Add(new object[] { rect2, Rectangle.WidthProperty, da }); this.PerformAnimations(0, list); } private void PerformAnimations(int index, List lstDefinitions) { object[] definition = lstDefinitions[index] as object[]; AnimationTimeline animation = definition[2] as AnimationTimeline; animation.Completed += delegate { // Start the other animation after the end of the previous animation. index++; if (lstDefinitions.Count > index) this.PerformAnimations(index, lstDefinitions); }; ((UIElement)definition[0]).BeginAnimation((DependencyProperty)definition[1], (AnimationTimeline)definition[2]); } The idea is to maintain a list of ‘animation definitiions’ and execute animations from this list recursively.