Getting User Info - windows authentication

Hi,

I am using ASP.Net Core and Entity Framework 6.0.

I am trying to get the windows user info, which will be checked against the application database for authorization access.

I am having problems with the following script:

BaseController.cs

public class BaseController: Controller
{

     public override void OnActionExecuting(ActionExecutingContext filterContext)
     {
            if (HttpContext.User == null || HttpContext.User.Identity.AuthenticationType != "Forms") 
            {
                    //return null; 
             }

             var identity = HttpContext.User.Identity;
      }
}


web.config

<configuration>
  <system.web>
    <authentication mode="Windows" />
    <authorization>
       <deny users="?"/>
    </authorization>
  </system.web>
</configuration>

When I run the application,

HttpContext.User.Identity.AuthenticationType = "" and HttpContext.User.Identity = "".  How can I get the current windows username?

Thanks,

tinac99