gci "hklm:\SOFTWARE\Microsoft\NET Framework Setup\NDP" | % {(Get-ItemProperty registry::$_).PSChildName}

gci "registry::HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\NET Framework Setup\NDP"| % {Get-ItemProperty registry::$_} |Select @{Name="Version";Expression={$_.PSChildName}}

http://msdn.microsoft.com/zh-cn/library/hh925568(v=vs.110).aspx

通过注册表查看已安装 .NetFramework 版本