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In this post Beat Kiener creates an attached behavior to support mouse wheel scrolling for any control like a combo box.

The behavior should use the native UIElement.MouseWheel without any javascript code, because javascript is not supported in out of browser scenario.

It sounds easy, but the problem is that the mouse wheel event is not bubbling up the visual tree as expected inside a popup control.

What is really cool about this approach is that each button can contain the logic used to flip the panel (Storyboard direction, duration, etc).

 I have demonstrated the technique many times, but here it is all packaged up in a nice reusable class.

By now most Silverlight developers should have stumbled on a great new feature of Silverlight 3 and Expression Blends, custom Triggers and Behaviors. I seriously don’t know how I lived without them!

Matt Casto posted about one cool new feature the became available with Silverlight 3 - pixel shaders, also known as shader effects.

The two most common effects – drop shadow and blur – are included with Silverlight. Its easy to add these effects to any UIElement.

I did a few searches tonight to get started playing with the Bitmap API and found several examples, but unfortunately none of them had any source code attached, and were written against previous SL3 betas which had different method signatures relevant to the bitmap rendering, so I wanted to go ahead and post a simple example of rendering out a UIElement to a bitmap. This example shows the output of rendering a TextBlock at various font sizes and image sizes and setting the resultant bitmaps as the source for three equal sized Image UIElements.

In some scenarios we need to find out what are the objects located at a specific point or in a certain area. In this case we get access to the System.Windows.UIElelement objects using the UIElement.HitTest method. It can test a Rect area or a Point. The return value is a collection of the children in this area arranged from the top element to the bottom.

C#

Rect areaInAbsoluteCoordinates = new Rect( areaLeftCoordinate, areaTopCoordinate, areaWidth, areaHeight );

IEnumerable<UIElement> childrenInArea = panel.HitTest(areaInAbsoluteCoordinates );

Note! In Silverlight the coordinates for hit testing are the absolute coordinates of the application. In case you want to hit test with coordinates relative to an UIElement see our tip.

Note! To get all the elements in an area you must use Application.Current.VisualRoot.HitTest.

That’s it!