XAML Browser Applications

XAML Browser Applications (XBAP, pronounced "ex-bap") are Windows Presentation Foundation (.xbap) applications that are hosted and run inside a web browser such as Firefox or Internet Explorer. Hosted applications run in a partial trust sandbox environment and are not given full access to the computer's resources like opening a new network connection or saving a file to the computer disk and not all WPF functionality is available. The hosted environment is intended to protect the computer from malicious applications; however it can also run in full trust mode by the client changing the permission. Starting an XBAP from an HTML page is seamless (with no security or installation prompt). Although one perceives the application running in the browser, it actually runs in an out-of-process executable (PresentationHost.exe) managed by a virtual machine. In the initial release of .NET Framework 3.0, XBAPs only ran in Internet Explorer. With the release of .NET Framework 3.5 SP1, which includes an XBAP extension, they also run in Mozilla Firefox.

XBAP limitations

XBAP applications have certain restrictions on what .NET features they can use. Since they run in partial trust, they are restricted to the same set of permission granted to any InternetZone application. Nearly all standard WPF functionality, however, around 99%, is available to an XBAP application. Therefore, most of the WPF UI features are available.

Permitted

• 2D drawing
• 3D
• Animation
• Audio

Not permitted

• Access to OS drag-and-drop
• Bitmap effects (these are deprecated in .NET 3.5 SP1)
• Direct database communication (unless the application is fully trusted)
• Interoperability with Windows controls or ActiveX controls
• Most standard dialogs
• Shader effects
• Stand-alone Windows

See also

• Silverlight
• XAML

External links

• Windows Presentation Foundation Security Sandbox
• Channel 9 WPF XBAP Video
• Run XBAP in IE, Firefox, Chrome, Opera and Maxthon