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Mainly check in the registry
For versions 1 through 4 of the .NET Framework see how
Navigate to the following node in the registry
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\NET Framework Setup\NDP
The installed .NET Framework is listed in the NDP directory
For .NET Framework 4.5 or later see how
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\NET Framework Setup\NDP\v4\Full
If there is no Full node, it means that version 4.5 or later has not been installed
Administrator privileges are required to open the registry
Attach the framework download address:
https://www.microsoft.com/zh-cn/search/result.aspx?q=net