XBAP is the technology formerly known as "Web Browser Applications" or WBA, (wubbas), and Karen Corby provides a slightly dated introductory whitepaper on MSDN. In simple terms, an XBAP application is written in XAML, hosted in a web browser sandbox, and does not need to be installed like a click-once application. It does, however, require the .NET 3.0 Framework to be installed on the target machine and will trigger a .NET 3.0 Framework download before the XBAP application initializes, which is an important item to be aware of when considering XBAP.
Rob Relyea, a Program Manager working on WPF read Anne Zelenka's blog posting on the .NET framework 3.0 launch and wrote a comparison of ActiveX with XBAP. In a nutshell when compared with ActiveX:
- XBAPs are easier to work with than DHTML
- XBAPS run in a secure sandbox
- XBAPS do not require approval prompts due to limited access to the local machine
- XBAPS can use 98.2% of the power of WPF when building user interfaces
- XBAPS must live inside an iFrame or top level window, which the WPF team hopes to fix in the future
- The XBAP hosting strategy is currently as a DocumentObject application meaning communication must be done via a querystring.
- XBAPS are only supported in IE6 or IE7 today.
How difficult is it to convert your WPF applications into XBAPs? Charles Petzold provided a follow up blog post last week detailing in 6 steps the process to convert an application to an XBAP.