尝试一下:
Vista如何生成文档图标与我的应用程序相关?

Try this:
How does Vista generate the icon for documents associated to my application?

可接受的答案说明了图标和文件关联.

The accepted answer explains icons and file associations.

您的应用使用WPF没关系.文件关联不在乎您的应用程序使用什么GUI框架.

It doesn't matter that your app uses WPF. The file associations don't care what GUI framework your app uses.