如何在C#中找到用户名/身份

using System.Security.Principal;

WindowsIdentity identity = WindowsIdentity.GetCurrent();
string username = identity.Name;

string username = Environment.GetEnvironmentVariable("USERNAME");

using System.DirectoryServices.AccountManagement;

PrincipalContext context = new PrincipalContext(ContextType.Domain);
UserPrincipal user = UserPrincipal.FindByIdentity(context, "username");
string username = user.Name;

using Microsoft.AspNetCore.Authentication;
using Microsoft.AspNetCore.Authentication.Cookies;
using Microsoft.AspNetCore.Http;

HttpContext httpContext = HttpContext.Current;
string username = httpContext.User.Identity.Name;