将我的代码更新为asp.net core 2.2，仍然无法获取此变量的值

如果您使用的是asp.net core 2.2或更高版本，请按以下方式获取 IServerVariablesFeature :

If you're using asp.net core 2.2 or above, get the IServerVariablesFeature as below:

var serverVars = HttpContext.Features.Get<IServerVariablesFeature>();
var iisVersion = serverVars == null ? null : serverVars["SERVER_SOFTWARE"]; 

演示: