Silverlight 4 features local file system access and out-of-browser execution. On Windows and Mac, developers can simply click the permissions box saying that an application is trusted so that it can gain access to local system resources. This capability takes Silverlight apps out of the sandbox. Code compatibility is another key feature in Silverlight 4. An assembly only needs to be compiled once in Silverlight 4 or the .NET framework in order to run on both platforms. Developers can interact with HTML elements in Silverlight 4 by hosting HTML as a control within applications. In addition, Silverlight 4 has a new profiler API that improves app optimization. Silverlight 4 also features multicast streaming that delivers media to thousands of clients without crashing the network.
Here are some more features in Silverlight 4:
- 30% faster startup time
- Support for the Google Chrome browser
- Integrated web cam and microphone support
- Support for right-click support
- Mouse wheel input for all standard Silverlight controls
- Drag and drop support
- Drop target support to enable streaming of selected files
- Programmatic printing support
- Programmatic access to the clipboard
- Rich text editing
- REST enhancements
- WCF RIA services
- Offline digital rights management
Silverlight is installed on approximately 45% of internet using computers worldwide. That figure is a far cry from Adobe's 98% install base for Flash Player. However, Silverlight is gaining recognition for its live, multi-angle streaming of Sunday Night Football and the Olympics.
Microsoft is already talking about the next version of Silverlight. It will leverage the Just In Time (JIT) CLR compiler to increase application performance. Streaming on devices without browser plugin support (e.g. Apple's iPhone) is another feature planned for Silverlight's next version. Scott Guthrie, a corporate VP of Microsoft, says the company intends to continue its pattern of frequent Silverlight releases. The final version of Silverlight 4 is slated for the first half of 2010.