Blazor WASM：ReadFromJsonAsync <List<Object>> Post crud 时出错

Question

我有这个Error

The Json value could not be converted to System.Collections.Genereic.List 1[Blazor_fresh_project.Shared.Feedback]. Path: $ | LineNumber: 0 | BytePositionInLine: 1.

当我尝试使用此方法创建对象时 :

public async Task<List<Feedback>> CreateFeedback(Feedback feedback)
        {
             var resulte = await _httpClient.PostAsJsonAsync($"api/feedback",feedback);
            string content = Newtonsoft.Json.JsonConvert.SerializeObject(resulte);
            Console.WriteLine("Here is THE CONTENT " +content);
             var   feedbacks = await resulte.Content.ReadFromJsonAsync<List<Feedback>>();
            return feedbacks;
        }

此错误发生在第 :

行

 var   feedbacks = await resulte.Content.ReadFromJsonAsync<List<Feedback>>();

控制台写： Console debug
对于调试此类错误，您有什么建议或技巧吗？

编辑：api/feedback request

namespace Blazor_fresh_project.Server.Controllers
{

    [Route("api/[controller]")]
    [ApiController]
    public class FeedbackController : ControllerBase
    {
        List<Feedback> Feedbacks = new List<Feedback> {
           new Feedback{Id=1,Name="arthur",Description="I think this is great",DateOfPost=DateTime.Now,Power=10},
           new Feedback{Id=2,Name="Mario",Description=" coming soon",DateOfPost=DateTime.Now,Power=8},
           new Feedback{Id=3,Name="Chipolo",Description="I think this is great",DateOfPost=DateTime.Now,Power=17},
           new Feedback{Id=4,Name="Coco",Description=" coming soon",DateOfPost=DateTime.Now,Power=12},
           new Feedback{Id=5,Name="Marguerite",Description="I think this is great",DateOfPost=DateTime.Now,Power=6},
           new Feedback{Id=6,Name="Carine",Description=" coming soon",DateOfPost=DateTime.Now,Power=4}
            };
        [HttpGet]
        public async Task<IActionResult> GetFeedbacks()
        {
            return Ok(Feedbacks);
        }

        [HttpGet("{id}")]
        public async Task<IActionResult> GetSingleFeedback(int id)
        {
            var feedback = Feedbacks.FirstOrDefault(f => f.Id == id);
            if (feedback == null)
                return NotFound("this feedback wasn't found");
            
            return Ok(feedback);
        }
        [HttpPost]
        public async Task<IActionResult> CreateFeedback(Feedback feedback)
        {
            feedback.Id = Feedbacks.Max(h => h.Id + 1);
            Feedbacks.Add(feedback);
            return Ok(feedback);
        }
    }
}


namespace Blazor_fresh_project.Client.Services
{
    public class FeedbackService : IFeedbackService
    {
        private HttpClient _httpClient;
        public FeedbackService(HttpClient httpClient)
        {
            _httpClient = httpClient;
        }
        [Authorize]
        public async Task<List<Feedback>> GetFeedbacks()
        {
          return await _httpClient.GetFromJsonAsync<List<Feedback>>("api/feedback");

        }

        public async Task<Feedback> GetFeedback(int id)
        {
            return await _httpClient.GetFromJsonAsync<Feedback>($"api/feedback/{id}");
        }
        [Authorize]
        public async Task<List<Feedback>> CreateFeedback(Feedback feedback)
        {
             var resulte = await _httpClient.PostAsJsonAsync($"api/feedback",feedback);
            string content = Newtonsoft.Json.JsonConvert.SerializeObject(resulte);
            Console.WriteLine("Here is THE CONTENT " +content);
             var   feedbacks = await resulte.Content.ReadFromJsonAsync<List<Feedback>>();
            return  feedbacks;
        }
    }
}

Answer 1

'Console' 屏幕截图向我们展示了单个反馈项的有效负载，浏览器中的请求显示了反馈列表。

您的代码正在执行 POST，浏览器执行 GET。显然，您的端点具有不同的 return 类型，用于 GET 和 POST.

~~Post 如果您需要更多帮助，请提供控制器的（相关）代码。~~

好的，你确实做到了。你可以改变你的控制器或者看起来更合乎逻辑的东西，你的客户：

    public async Task<Feedback> CreateFeedback(Feedback feedback)
    {
      var resulte = await _httpClient.PostAsJsonAsync($"api/feedback",feedback);
      var feedback = await resulte.Content.ReadFromJsonAsync<Feedback>();
      return feedback;
    }

并相应地调整调用代码。

Blazor WASM：ReadFromJsonAsync <List<Object>> Post crud 时出错

Blazor WASM : error while ReadFromJsonAsync <List<Object>> Post crud

c#

json

crud

httprequest

blazor