how can i find my .net frame work version

how can i find the version of my .net frame w开发者_运维知识库ork

look in the web.config

<add assembly="System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/>

if you need to check it programmatically:

        Microsoft.Win32.RegistryKey registryKey;

        registryKey = Microsoft.Win32.Registry.LocalMachine.OpenSubKey(@"SOFTWARE\Microsoft\NET Framework Setup\NDP\", false );

        string[] installedNetVersions = registryKey.GetSubKeyNames();

System.Environment.Version will give you the CLR version your application is running under - this may not be the same as the ASP.NET version.