The Joy Of Programming

Behaviors is one of the new features Expression blend 3 has introduced to make interactivity easy. Behavior allows us to wrap the interaction logic as a very discrete unit and attach to any UI elements. My previous blog post about Attaching preview behavior to a Slider control , is a good scenario to make as a Behavior. I have used Attached Dependency property as a technique to make it happen in the earlier post, though the concept is almost same but Blend Behavior gives a neat and clean abstraction. It also allows a Blend user to just drag-drop to any Slider control. So this is a great functionality which helps boost the re-usability in a cool way. Problem : Create a behavior to display the value of a Slider control when hover over. First step is to make a class which derived from Behavior class. public class PreviewSliderBehaviour : Behavior<Slider> Here I am explicitly giving Slider class as my targeted UI Element type since this behavior is meaningless to other elements. ...

Technorati Tags: MediaPlayer Style , Theme , WPF , XAML , ControlTemplate Today I am sharing about a common usage of Slider control for the Timeline scenarios as we can see in many Media players. The above pictures shows timeline/scrubber control of some popular video players( Hulu and Youtube ). We can edit the Slider Style and ControlTemplate to create the same look and feel of the above two scrubbers except the preview value get displayed when we hover over. While figuring out an easy way to build this, I got two different options. The first and the obvious solution is to extend the Slider class to create a new custom control, which will have a new DependancyProperty called PreviewValue to hold the mouse over value. The biggest challenge in this approach is to make this control as much flexible(design and dev friendly) because people may customize the control by giving different Size and Margins to the Track and other parts of the Control template, which will make our assumpti...

Imagine that you have a lot of properties in a class and you are very sure that all of those properties are getting updated at the same point of time. What generally we do in the ViewModel scenario is that we create Property setters for all these and raise PropertyChanged event so as to get the data reflected in the UI layer bindings. But that is a real resource waste when you really know the time of all your property updates. The solution is really easy as per the MSDN documentation for PropertyChanged Event in the remarks section it says “ The PropertyChanged event can indicate all properties on the object have changed by using either a null reference (Nothing in Visual Basic) or String.Empty as the property name in the PropertyChangedEventArgs .” It seems that this is a great saver in terms of code writing and execution, since we need to raise only one PropertyChanged Event per class just after the property updation. Think about a Stock Trading scenario as an example to this, yo...