We are currently working with Wix (Windows Installer XML) and  today we wanted to roll out a new software package with a prerequisite for Silverlight 3.0.

I must say it’s pretty hard to find something on the web, on how to check installation or version of Silverlight (for Wix or other deployment projects).

But Alex and I found the solution.

If Silverlight is installed you will find the following Registry Entry:

[HKEY_CLASSES_ROOT\AgControl.AgControl\CurVer]

@=”AgControl.AgControl.x.x”

The “AgControl.AgControl.x.x” part contains the current installed version (Silverlight 3.0 = AgControl.AgControl.3.0)

As a little extra here the “Condition” check for Wix:

<Property Id="SILVERLIGHTVERSION">
  <RegistrySearch Id="SilverLightSearch" Type="raw" Root="HKCR" Key="AgControl.AgControl\CurVer"/>
</Property> 

<Condition Message="Please install Silverlight 3.0 or higher, available at: http://go.microsoft.com/fwlink/?LinkID=149156&amp;v=3.0.40818.0">
  <![CDATA[Installed OR SILVERLIGHTVERSION >= "AgControl.AgControl.3.0"]]>
</Condition>