错误 CS0234：命名空间“System.Web”中不存在类型或命名空间名称“Mvc”

Question

我正在使用 VS Code 创建一个 asp.net 项目。这个问题首先被提出是因为我需要使用 AllowAnonymous 操作过滤器。它给出了“ The type or namespace name 'AllowAnonymousAttribute' could not be found.”的错误所以我添加了使用 System.Web.Mvc; 在开始部分。它显示error CS0234: The type or namespace name 'Mvc' does not exist in the namespace 'System.Web'你能给出任何建议吗？谢谢。

using System;

using System.Collections.Generic;

using System.Linq;

using System.Web.Mvc;

using System.Threading.Tasks;

using Microsoft.AspNetCore.Mvc;

using DatingApp.API.Data;

using Microsoft.EntityFrameworkCore;

namespace DatingApp.API.Controllers

{

    [AllowAnonymous]

    [Route("api/[controller]")]

    public class ValuesController : Controller

    {

        private readonly DataContext _context;

        public ValuesController(DataContext context)

        {

            _context = context;

        }

        // GET api/values

        [HttpGet]

        public async Task<IActionResult> GetValues()

        {

            var values=await _context.Values.ToListAsync();

            return Ok(values);

        }

......

运行后dotnet watch run，它给出了如下错误。

watch : Started

Controllers\ValuesController.cs(4,18): error CS0234: The type or namespace name 'Mvc' does not exist in the namespace 'System.Web' (are you missing an assembly reference?) [C:\Xumin\projects\DatingApp\DatingApp.API\DatingApp.API.csproj]

Controllers\ValuesController.cs(12,6): error CS0246: The type or namespace name 'AllowAnonymousAttribute' could not be found (are you missing a using directive or an assembly reference?) [C:\Xumin\projects\DatingApp\DatingApp.API\DatingApp.API.csproj]

Controllers\ValuesController.cs(12,6): error CS0246: The type or namespace name 'AllowAnonymous' could not be found (are you missing a using directive or an assembly reference?) [C:\Xumin\projects\DatingApp\DatingApp.API\DatingApp.API.csproj]