For the last six months or so I have been interacting a lot with other developers through webcasts and my WPF class. Time and time again I am asked “why do you concentrate on XAML and not use the wizards”. Well first it’s because the Visual Studio Extensions for WPF are really not there yet but more importantly is because you need to know it.
If you think about how you are going to develop WPF applications you will realize you are going to use some tool to assist you in the process. Most of the tools in the marketplace all emit XAML when it comes to designing the UI and if you either use a tool to create a UI snippet or you get one off the Internet you will inevitably need to modify it. Without knowledge of XAML you are going to be lost. Think about HTML and the designers for it. They all emit HTML but you still find yourself working with HTML one way or another.
So how do you work your way through the maze of XAML and what to do with it? I would suggest reading XAML Overview in the SDK. It has quite a few nice sections on what it is and how it works. The next thing you can do is download some samples from WPF on .NET FX and see how elements are put together.