XAML Browser Applications (XBAP, pronounced "ex-bap") are

Windows Presentation Foundation Windows Presentation Foundation (WPF) is a free and open-source graphical subsystem (similar to WinForms) originally developed by Microsoft for rendering user interfaces in Windows-based applications. WPF, previously known as "Avalon", was initia ...

(.xbap) applications that are hosted and run inside a

web browser A web browser is application software for accessing websites. When a user requests a web page from a particular website, the browser retrieves its files from a web server and then displays the page on the user's screen. Browsers are used o ...

such as

Firefox Mozilla Firefox, or simply Firefox, is a free and open-source web browser developed by the Mozilla Foundation and its subsidiary, the Mozilla Corporation. It uses the Gecko rendering engine to display web pages, which implements current ...

Internet Explorer Internet Explorer (formerly Microsoft Internet Explorer and Windows Internet Explorer, commonly abbreviated IE or MSIE) is a series of graphical web browsers developed by Microsoft which was used in the Windows line of operating systems (in ...

. 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 The HyperText Markup Language or HTML is the standard markup language for documents designed to be displayed in a web browser. It can be assisted by technologies such as Cascading Style Sheets (CSS) and scripting languages such as JavaS ...

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 computing, a virtual machine (VM) is the virtualization/ emulation of a computer system. Virtual machines are based on computer architectures and provide functionality of a physical computer. Their implementations may involve specialized h ...

. In the initial release of

.NET Framework 3.0 Microsoft started development on the .NET Framework in the late 1990s originally under the name of Next Generation Windows Services (NGWS). By late 2001 the first beta versions of .NET 1.0 were released. The first version of .NET Framework was ...

, 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. Starting in February 2009, XBAP applications no longer function when run from the Internet. Attempting to run the XBAP will cause the browser to present a generic error message. An option exists in Internet Explorer 9 that can be used to allow the applications to run, but this must be done with care as it increases the potential

attack surface The attack surface of a software environment is the sum of the different points (for " attack vectors") where an unauthorized user (the "attacker") can try to enter data to or extract data from an environment. Keeping the attack surface as small a ...

- and there have been security vulnerabilities in XBAP.

Permitted

*2D drawing *3D *Animation *Audio

Not permitted

*Access to OS

drag-and-drop In computer graphical user interfaces, drag and drop is a pointing device gesture in which the user selects a virtual object by "grabbing" it and dragging it to a different location or onto another virtual object. In general, it can be used to ...

*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 ActiveX is a deprecated software framework created by Microsoft that adapts its earlier Component Object Model (COM) and Object Linking and Embedding (OLE) technologies for content downloaded from a network, particularly from the World Wide We ...

controls *Most standard dialogs *Shader effects *Stand-alone Windows

References

External links

Windows Presentation Foundation Security Sandbox

Channel 9 WPF XBAP Video
.NET Framework terminology Microsoft application programming interfaces {{web-software-stub

XBAP limitations

Permitted

Not permitted

See also

References

External links