Silverlight will be the primary development technology for Windows Phone. Initially, only a subset of Silverlight 3 features plus the new features of Silverlight 4 will be will available. The supported features of Silverlight 3 will be:
- Input
- UI rendering
- Media
- Deep Zoom
- Controls
- Layout
- Data binding
- Isolated storage
- Networking (HttpWebRequest, WebClient)
- XAML
- XAP packaging
- XML serialization
- Windows Communication Foundation (WCF)
In addition, there are several new Silverlight features which are unique to Windows Phone, namely
- Gesture controls
- Software input panel (SIP) support on the TextBox control
- Manipulation events
- Windows Phone Class Library (this is a library of classes specific to working with the Windows Phone UI)