The FocusVisualElement is the equivalent of the dotted line that you see in Windows interfaces and on browser pages around an object on the page that “has the focus”. This means that it will receive the input a user is giving with a mouse, keyboard or touch. Actually, web designers don’t really like these dotted lines, because they degrade the look of their interface. It may disturb the carefully crafted look and feel of the page. But this FocusVisualElement has a function.
Normally I’m not so eager to use buttons as controls for showing examples. It usually doesn’t lead to an interesting visual result. As a designer my examples should look more interesting. Fortunately in Silverlight you can create other shaped and colored buttons easily using the Make into Control… option in the contextmenu of graphic elements gathered in a Grid. In this case the I’d like to focus on the FocusVisualElement element, so Buttons are my first choice.
In Silverlight the FocusVisualElement is an actual graphical element that is part of a control’s ControlTemplate. In Blend you can access this template by selecting Edit Template/Edit Current (I’d really like a keyboard shortcut here, but there isn’t, yet).
In template editing mode you can find the FocusVisualElement in every Silverlight control. It’s shape depends on the type of control, but in a Button it is a light blue Rectangle. By default this Rectangle has its Opacity set to Zero and the Focused State makes it visible. This leads to the notion that you can change the looks of this Focused State to anything you’d like:
In these images I show how a HyperlinkButton could get a Glow Effect when it is focused. But there’s no reason to leave it at that. The oval Button plays an animation when it is focused. Apart from the Opacity, a TranslationX, Scale and a PointAnimation is applied to a semitransparent Ellipse when the Focused State is triggered. This makes the Ellipse move van left to right. The animation is AutoReversed and repeated Forever.
You can use the VisualStateManager to create the animations. You can also show the TimeLine and create an Storyboard that you paste in de <VisualState x:Name="Focused" /> Visual State. When you create a Button using Make into Control… you can copy the Visual States out of the ControlTemplate of a normal Button and use them in your own.
Make sure your animation for the Focused State of controls are low-key. You don’t want to irritate your users with flashing graphics only because a control is focused!