A Couple of Avalon Express (XBAP) Demos

Some technologies are cut, others just get renamed so many times that people think they've been cut!

Ever since the first public unveiling of Windows Presentation Foundation, we've supported both standalone and browser-based applications. On the browser side, applications run in a partial-trust sandbox that allows a subset of WPF functionality to be supported securely. From Visual Studio, simply create a new project of type "WinFX Web Browser Application" (this presumes you've installed WinFX and the WinFX Extensions for Visual Studio) to create one of these projects.

In order to confuse as many people as possible, this technology has had myriad names over the last few public releases. In Beta 1, it was known as "Avalon Express", and the applications had a file extension of .xapp. However the Express name overlapped with our use of the word "express" to describe the lightweight versions of our developer tools, so in the PDC / September CTP release they were renamed to the simpler, more descriptive "Web Browser Application", with a .wba file extension. Time passes, and it turns out that the .wba extension is used by another product already, so to avoid application conflict, they were renamed again in the recent November CTP release to "XAML Browser Application", with a .xbap file extension. It's the third version of the name, so hopefully we've got it right this time.

Updated: I've enclosed some new samples here - the original ones I linked to are no longer compatible with more recent builds. Thanks to TheWPFBlog for these great samples that run on Windows Vista RC1.

Comments (18)
  1. Anonymous says:

    I hope you dont mind but i created a xaml gadget for http://www.live.com based on your 14 line rss reader. http://microsoftgadgets.com/forums/1585/ShowPost.aspx

  2. Anonymous says:

    Let’s hope they come up with YAN (yet another name) since XBAP is both difficult and ugly. Dropping or replacing the B(rowser) would make me happy though.

  3. Anonymous says:

    What should I do for those examples to work ? I am new in the world of WPF and is a mess in my head..I want to mention that I have dec ctp installed. Thanks!

  4. Anonymous says:

    Ive got the Jan CTP installed. Its working fine (the Avalon bit anyway) as its comes up with an error when I try either of these XBAPs:


    Below is a summary of the errors, details of these errors are listed later in the log.

    * An exception occurred while downloading the manifest. Following failure messages were detected:

    + Downloading http://www.mobiform.com/demos/avalonclock/webavalonclock.xbap did not succeed.

    + The remote server returned an error: (407) Proxy Authentication Required.

    Now I am using a proxy, but its setup in IE options, and works fine for regular web browsing. I’m assuming that Avalon is not clever enough to use these settings?

  5. Anonymous says:

    .Net config does not use default proxy. You have to add it yourself.

    Add to machine.config (X:WINDOWSMicrosoft.NETFrameworkv2.0.xxxxxCONFIG) the following lines:




         <defaultProxy enabled="true" useDefaultCredentials="true"/>



  6. Anonymous says:

    I get an error when trying to check those samples. I get an "TRUST NOT GRANTED" error. Here is more about error:


    Windows : 5.1.2600.131072 (Win32NT)

    Common Language Runtime : 2.0.50727.42

    System.Deployment.dll : 2.0.50727.42 (RTM.050727-4200)

    mscorwks.dll : 2.0.50727.42 (RTM.050727-4200)

    dfshim.dll : 2.0.50727.42 (RTM.050727-4200)


    Deployment url : http://www.mobiform.com/demos/avalonclock/webavalonclock.xbap

    Application url : http://www.mobiform.com/demos/avalonclock/WebAvalonClock_1_0_2_2006/WebAvalonClock.exe.manifest


    Deployment Identity : WebAvalonClock.application, Version=, Culture=neutral, PublicKeyToken=f25912057f38dd95, processorArchitecture=msil

    Application Identity : WebAvalonClock.exe, Version=, Culture=neutral, PublicKeyToken=f25912057f38dd95, processorArchitecture=msil, type=win32


    * Online only application.

    * Browser-hosted application.


    Below is a summary of the errors, details of these errors are listed later in the log.

    * An exception occurred while determining trust. Following failure messages were detected:

    + User has refused to grant required permissions to the application.


    No transaction error was detected.


    There were no warnings during this operation.


    No phase information is available.


    Following errors were detected during this operation.

    * [17.03.2006 16:36:52] System.Deployment.Application.TrustNotGrantedException (Unknown subtype)

    – User has refused to grant required permissions to the application.

    – Source: System.Deployment

    – Stack trace:

    at System.Deployment.Application.ApplicationTrust.RequestTrust(SubscriptionState subState, Boolean isShellVisible, Boolean isUpdate, ActivationContext actCtx, TrustManagerContext tmc)

    at System.Deployment.Application.DeploymentManager.DetermineTrustCore(Boolean blocking, TrustParams tp)


    No transaction information is available.

  7. Anonymous says:

    I have the similar problem as above – "Trust Not Granted" error, Could you please let me know how to resolve this issue.

    My Email : malik_daredia@satyam.com

  8. Anonymous says:

    I also have the similar problem as above – "Trust Not Granted" error, would you please let me know how to resolve it?

    My Email : xuyuzhen@boco.com.cn

  9. Anonymous says:

    My colleague Tim Sneath posted a blog back in Nov 2005 which I think captures this pretty well. Here…

  10. Anonymous says:

    I am developing software using winfx I would like to know how to create a xbap file .

    Do you have some code sample that can I download?



    email: smartstore@hotmail.com

  11. Anonymous says:

    I did not solve the problem "Proxy Authentication Required" after i edit the machine.config as above, how to resolve it?

    My Email:guojingwei@boco.com.cn

  12. Anonymous says:


       i am trying to open the webfpaintfactory.xbap in my browser.But its giving me error stating that "Trust not granted". Can someone please help me to sort this problem.Also i m building WinFX browser application and so do want some of the source codes or the links through which i could have the sample source code or for the clock and web paint factory.

    Thanks in advance.

    One can mail me at: saloni@adiance.com

  13. Anonymous says:

    I saw many people have problem with "TRUST NOT GRANTED". Is anyone get the solution yet ? Please post the solution is you have one.

    Thank You,

    you can email my at jyu@aws.com.

  14. Anonymous says:

    Yeah, I would like to see these demos, but "trust is not granted". Leave a comment at my space 😛

  15. Anonymous says:

    Is there going to be any way for non-Windows users to experience XBAP applications? If not, would it really be worth it to deploy XBAP applications when one could deploy a Flash/Shockwave/Ajax app that could accomplish the same user experience and reach a wider user base?

  16. Anonymous says:

    Hello –

    How does this compare with WPF/e? Are these XBAP applications supported on multiple platforms?



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