The DevExpress Demo Center includes the “MVVM Best Practices” demo. The demo contains over 100 modules that illustrate major MVVM concepts (data binding, commands, services, etc.).
The demo also includes the Walkthrough section that breaks down a sample demo application into bite-sized steps. Each step is presented as a separate demo. You can test a compiled application, inspect relevant code, and read a detailed step description in corresponding tabs below the main demo region.