检测电脑安装的net framework版本

https://msdn.microsoft.com/en-us/library/hh925568(v=vs.110).aspx

To find .NET Framework versions by viewing the registry (.NET Framework 1-4)

1. On the Start menu, choose Run.
2. In the Open box, enter regedit.exe.

   You must have administrative credentials to run regedit.exe.

3. In the Registry Editor, open the following subkey:

   HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\NET Framework Setup\NDP

   The installed versions are listed under the NDP subkey. The version number is stored in the Version entry. For the .NET Framework 4 the Versionentry is under the Client or Full subkey (under NDP), or under both subkeys.

   Note
   The "NET Framework Setup" folder in the registry does not begin with a period.

To find .NET Framework versions by viewing the registry (.NET Framework 4.5 and later)

1. On the Start menu, choose Run.
2. In the Open box, enter regedit.exe.

   You must have administrative credentials to run regedit.exe.

3. In the Registry Editor, open the following subkey:

   HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\NET Framework Setup\NDP\v4\Full

   Note that the path to the Full subkey includes the subkey Net Framework rather than .NET Framework.

   Note
   If the Full subkey is not present, then you do not have the .NET Framework 4.5 or later installed.

   Check for a DWORD value named Release. The existence of the Release DWORD indicates that the .NET Framework 4.5 or newer has been installed on that computer.

   

   The value of the Release DWORD indicates which version of the .NET Framework is installed.

   Value of the Release DWORD	Version
   378389	.NET Framework 4.5
   378675	.NET Framework 4.5.1 installed with Windows 8.1 or Windows Server 2012 R2
   378758	.NET Framework 4.5.1 installed on Windows 8, Windows 7 SP1, or Windows Vista SP2
   379893	.NET Framework 4.5.2
   On Windows 10 systems: 393295 On all other OS versions: 393297	.NET Framework 4.6
   On Windows 10 November Update systems: 394254 On all other OS versions: 394271	.NET Framework 4.6.1
   On Windows 10 Anniversary Update: 394802 On all other OS versions: 394806	.NET Framework 4.6.2

To find .NET Framework versions by querying the registry in code (.NET Framework 1-4)

• Use the Microsoft.Win32.RegistryKey class to access the Software\Microsoft\NET Framework Setup\NDP\ subkey under HKEY_LOCAL_MACHINE in the Windows registry.

  The following code shows an example of this query.