ASP.NET Core 3.1“'User'不包含'FindFirstValue'的定义”“

Question

[尝试从此处实施答案时>How to get the current logged in user Id in ASP.NET Core并且用户将我重定向到此处> https://github.com/dotnet/aspnetcore/issues/18348

var UserId = User.FindFirstValue(ClaimTypes.Name);

^这不起作用，并显示以下错误'User' does not contain a definition for 'FindFirstValue'

我的控制器正在调用的完整代码段...

using Microsoft.EntityFrameworkCore;
using ProjectName.Data;
using ProjectName.Repo;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
//using System.Web;
using System.Threading.Tasks;
using System.Security.Claims;
using Microsoft.AspNetCore.Http;
using System.Web.Providers.Entities;

namespace ProjectName.Processing
{
    public class ControllerNameProcessing
    {
        private readonly ProjName_DevelContext _context = new ProjName_DevelContext();
        private async Task<List<2ndClassNameRepository>> GetNameFromRepo()
        {
            List<2ndClassNameRepository> repoList = new List<2ndClassNameRepository>();
            var Temp = await _context.tablename.ToListAsync();
            /* Working Test
            2ndClassNameRepository repo = new 2ndClassNameRepository();
            repo.UserName = "JohnDoe";
            repoList.Add(repo);
            return repoList;
            */
            2ndClassNameRepository repo = new 2ndClassNameRepository();
            // repo.UserName = "JohnDoe";
            var userId = User.FindFirstValue(ClaimTypes.Name);
            repo.UserName = userId;
            repoList.Add(repo);
            return repoList;
        }
        internal async Task<List<2ndClassNameRepository>> GetUserName()
        {
            return await GetNameFromRepo();
        }
    }
}

知道为什么会出现此错误吗？

Answer 1

尝试如下获取用户ID

 var userId = User.Claims.Where(c => c.Type == "sub").FirstOrDefault().Value;

Answer 2

好！遇到问题了。UserClaimPrinciple仅在Controller上下文中可用。我看到您的ControllerNameProcessing不是Controller类。因此，您应该执行以下操作：

public class ControllerNameProcessing
{
     private readonly IHttpContextAccessor _httpContextAccessor;

     public ControllerNameProcessing(IHttpContextAccessor httpContextAccessor)
     {
         _httpContextAccessor = httpContextAccessor;
     }

     private async Task<List<2ndClassNameRepository>> GetNameFromRepo()
     {
         // Omitted your other codes for brevity

         var userName = _httpContextAccessor.HttpContext.User.FindFirstValue(ClaimTypes.Name);

        // Omitted your other codes for brevity
     }
}

然后您应按以下步骤在IHttpContextAccessor类中注册Startup：

public void ConfigureServices(IServiceCollection services)
{
    services.AddHttpContextAccessor();
}