What version of .NET is installed on a user’s system?

This article illustrates one approach in determining what Microsoft® .NET Framework version is installed on a user’s system. Also, it describes how to determine whether service packs are installed for your .Net Framework installation.

MsiNetAssemblySupport Property:
Starting with Windows Installer 2.0 and later, MsiNetAssembly property is available. If the .NET Framework is not installed, the MsiNetAssemblySupport property will not be set. On machines that have .NET Framework installed, Windows Installer sets the value of the MsiNetAssemblySupport property to the file version of Fusion.dll. When multiple versions of Fusion.dll are installed side-by-side on user’s machine, this property is set to the latest version of Fusion.dll file by Windows Installer.


For .NET Framework 1.0, the possible values of MsiNetAssemblySupport property are as
follows:

For .NET Framework 1.1, the possible values of MsiNetAssemblySupport property are as
follows:

For additional information, click the following link to view the article in the Microsoft
Knowledge Base:
http://support.microsoft.com/kb/318785