WPF is a brand-new user interface technology from Microsoft that first appeared when Vista was launched, but which is equally at home on all modern Windows operating systems as it's part of .NET 3.0. Technically speaking, WPF (Windows Presentation Foundation) is a set of .NET classes that redefines the way software user interfaces are designed and built by harnessing the power of XAML.

Windows provides a set of standard user-interface controls (buttons, list box, combo boxes, etc), which can be customised to a limited extent (colour, font, etc). Although it has always been possible to create user interfaces that are much more stylised, the amount of extra programming required has meant that most user interfaces utilise the standard controls and so often look alarmingly similar.

For example, a standard Windows combo box can contain only text items in the drop-down list. If you wanted, for example, to have graphics in the drop-down as well as text, a significant amount of custom code would need to be written, or a 3rd party component used - if a suitable one happened to be available.

WPF makes it very much easier to create user interfaces that are distinctive and more intuitive. If you want a combo box that displays a list of images in its drop-down list, it’s a single line of code. If you want a list box that scrolls a list of movies horizontally – again, it’s just a few lines of code.

As a result, WPF makes it easy to create very powerful and highly distinctive user interfaces without huge amounts of additional development. Information can be presented to the user in much more intuitive and powerful ways – ways that would be just too complex to implement using traditional technologies.