How do I detect what .NET version the application is running on?

I tried using Environment.Version.ToString() to det开发者_JAVA百科ermine what .NET framework on the target machine is in use, but it says I'm using .NET 2.0, when version 4.0 is installed.

How do I detect what version of the .NET Framework is running on the target machine?

Environment.Version.ToString(); returns version of your application not system, you can read the version from registry or search in %windows%\Microsoft.NET\Framework folders to find maximum number.

The registry key is HKLM\Software\Microsoft\NET Framework Setup\NDP\ see How to detect what .NET Framework versions and service packs are installed?

To find out what versions of .NET are available on a machine, you need to look in the registry - see Determine which versions and service pack levels of .NET Framework are installed.
_{(Originally MSDN KB article 318785)}