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Silverlight 4 Coded UI Tests + IE9: “No Silverlight controls were detected.”

I was playing around with the new (well, new-ish) Silverlight 4 Coded UI Tests that came with Visual Studio 2010 Feature Pack 2 this weekend. 

I trying to create a Coded UI test using the recorder and kept getting the following error:


No Silverlight controls were detected. Verify that the application under test is built using Silverlight assemblies with a version of 4.0 or greater and that a reference to the Microsoft.VisualStudio.TestTools.UITest.Extension.SilverlightUlAutomationHelper.dll assembly has been added to the project. For more information, see

I actually had added the reference to SilverlightUIAutomationHelper.dll from my Silverlight application (NOTE: it’s the Silverlight client project not the Coded UI test project) already.  So that wasn’t the problem. 

Next I found that my strong opinion that you shouldn’t name your Silverlight controls (no x:Name’s) was probably causing a problem.  This page talked me through what I needed for naming and, conveniently enough, Expression Blend has a utility that will do it for you.   

I still had the error.  Now I started wondering if it had something to do with running IE9 beta. 

The Answer: Yes.  In order to use the Coded UI Test Builder with Silverlight 4, you have to run Internet Explorer 9 (IE9) in Compatibility Mode.

Run your application and click the Compatibility Mode button in the URL box (see image below). 


Re-run the Coded UI Builder and now you’ll be able to do a coded UI test.


I hope this helps.



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One response to “Silverlight 4 Coded UI Tests + IE9: “No Silverlight controls were detected.””

  1. Aaron Kowall Avatar

    Was the x:Name an issue? You mention that you thought it was originally. However, would having no names have worked in Compat mode in IE9?

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