查看电脑安装的.net版本

其实很简单，但是中文搜索的内容比较啰嗦，七嘴八舌，不是官方。

下面是官方的检查办法：

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

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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