拷贝文件到C:\Windows目录里，DOS窗口输入dism /online /Enable-Feature /FeatureName:NetFx3 /Source:G:\ sources\sxs
dism /online /Enable-Feature /FeatureName:netFramework-v3.5 /Source:G:\sources\sxssG:\ sources\sxs
离线状态下安装.net3.5
原文：https://www.cnblogs.com/boosli/p/10201482.html
