Tuesday, 9 July 2013

Introduction to Windows Presentation Foundation (WPF)



The Windows Presentation Foundation is Microsoft’s next generation UI framework to create applications with a rich user experience. It is part of the .NET framework 3.0 and higher.
WPF combines application UIs, 2D graphics, 3D graphics, documents and multimedia into one single framework. Its vector based rendering engine uses hardware acceleration of modern graphic cards. This makes the UI faster, scalable and resolution independent.
The following illustration gives you an overview of the main new features of WPF

  
Separation of Appearance and Behavior
WPF separates the appearance of a user interface from its behavior. The appearance is generally specified in the Extensible Application Markup Language (XAML), the behavior is implemented in a managed programming language like C# or Visual Basic. The two parts are tied together by data binding, events and commands. The separation of appearance and behavior brings the following benefits:
  • Appearance and behavior are loosely coupled
  • Designers and developers can work on separate models.
  • Graphical design tools can work on simple XML documents instead of parsing code.

Rich composition
Controls in WPF are extremely composable. You can define almost any type of controls as content of another. Although these flexibility sounds horrible to designers, it’s a very powerful feature if you use it appropriate. Put an image into a button to create an image button, or put a list of videos into a combobox to choose a video file.


<Button>
    <StackPanel Orientation="Horizontal">
        <Image Source="speaker.png" Stretch="Uniform"/>
        <TextBlock Text="Play Sound" />
    </StackPanel>
</Button>



Highly customizable
Because of the strict separation of appearance and behavior you can easily change the look of a control. The concept of styles let you skin controls almost like CSS in HTML. Templates let you replace the entire appearance of a control.
The following example shows a default WPF button and a customized button.



Resolution independence
All measures in WPF are logical units - not pixels. A logical unit is a 1/96 of an inch. If you increase the resolution of your screen, the user interface stays the same size - it just gets crispier. Since WPF builds on a vector based rendering engine it's incredibly easy to build scalable user interfaces.





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