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.
How do I listen to click events on all the MenuItems through the parent ContextMenu?
Instead of setting up event handlers on all the MenuItems you can listen to those events as they bubble up to the context menu as follows: [XAML] MenuItem1 MenuItem2 MenuItem3 MenuItem4 Or you can setup the same thing in code as follows: [C#] menuItem1.AddHandler(MenuItem.ClickEvent, new RoutedEventHandler(MnItem_Click)); The event handler would then be something like: private void MnItem_Click(object sender, RoutedEventArgs e) { MenuItem item = e.Source as MenuItem; …. }
How do I listen to click events on all the tree nodes through the parent tree?
Instead of setting up event handlers on all the tree nodes you can listen to those events as they bubble up to the tree as follows: [XAML]<TreeView TreeViewItem.Selected=”TvItem_Selected”> <TreeViewItem>Node1</TreeViewItem> <TreeViewItem>Node2</TreeViewItem> <TreeViewItem>Node3</TreeViewItem> <TreeViewItem>Node4</TreeViewItem></TreeView> Or you can setup the same thing in code as follows: [C#] treeView1.AddHandler(TreeViewItem.SelectedEvent, new RoutedEventHandler(TvItem_Selected)); The event handler would then be something like: private void TvItem_Selected(object sender, RoutedEventArgs e) { TreeViewItem item = e.Source as TreeViewItem; …. }