一、使用HttpContextAccessor

在Program.cs中增加一行：

//获取IP使用
builder.Services.AddSingleton<IHttpContextAccessor, HttpContextAccessor>();

var builder = WebApplication.CreateBuilder(args);

// Add services to the container.
builder.Services.AddControllersWithViews();

//获取IP使用
builder.Services.AddSingleton<IHttpContextAccessor, HttpContextAccessor>();

var app = builder.Build();

// Configure the HTTP request pipeline.
if (!app.Environment.IsDevelopment())
{
    app.UseExceptionHandler("/Home/Error");
}
app.UseStaticFiles();

app.UseRouting();

app.UseAuthorization();

app.MapControllerRoute(
    name: "default",
    pattern: "{controller=Home}/{action=Index}/{id?}");

app.Run();

修改Controller:

private readonly IHttpContextAccessor _httpContextAccessor;

_httpContextAccessor = httpContextAccessor;

var ip = _httpContextAccessor.HttpContext.Connection.RemoteIpAddress.ToString();

using AspNetCoreMvcClientIp2.Models;
using Microsoft.AspNetCore.Mvc;
using System.Diagnostics;

namespace AspNetCoreMvcClientIp2.Controllers
{
    public class HomeController : Controller
    {
        private readonly ILogger<HomeController> _logger;
        private readonly IHttpContextAccessor _httpContextAccessor;
        public HomeController(ILogger<HomeController> logger, IHttpContextAccessor httpContextAccessor)
        {
            _logger = logger;
            _httpContextAccessor = httpContextAccessor;
        }

        public IActionResult Index()
        {
            //注入
            var ip = _httpContextAccessor.HttpContext.Connection.RemoteIpAddress.ToString();
            ViewBag.myip = "ip:" + ip;

            //直接实例化HttpContextAccessor
            IHttpContextAccessor ih = new HttpContextAccessor();
            string ip2 = ih.HttpContext.Connection.RemoteIpAddress.ToString();
            ViewBag.myip = "ip2:" + ip2;

            //使用ControllerBase的HttpContext
            var ip3 = HttpContext.Connection.RemoteIpAddress.ToString();
            ViewBag.myip = "ip3:" + ip3;

            return View();
        }

        public IActionResult Privacy()
        {
            return View();
        }

        [ResponseCache(Duration = 0, Location = ResponseCacheLocation.None, NoStore = true)]
        public IActionResult Error()
        {
            return View(new ErrorViewModel { RequestId = Activity.Current?.Id ?? HttpContext.TraceIdentifier });
        }
    }
}

也可以直接实例化HttpContextAccessor：

//直接实例化HttpContextAccessor
            IHttpContextAccessor ih = new HttpContextAccessor();
            string ip2 = ih.HttpContext.Connection.RemoteIpAddress.ToString();
            ViewBag.myip = "ip2:" + ip2;

二、使用ControllerBase的HttpContext

//使用ControllerBase的HttpContext
            var ip3 = HttpContext.Connection.RemoteIpAddress.ToString();
            ViewBag.myip = "ip3:" + ip3;

。