从Xamarin.Forms访问Web API的错误请求

Question

在这里，我解释了我的情况-我有2个项目-API （存储Web API）和APP （存储Xamarin.Forms）。 我已经使用EDMX从我的数据库中的API.Models文件夹中的API项目中创建数据模型。 我想从APP项目访问API，因此在我的APP项目中创建了类似的数据模型类。 当模型类中没有外键时，一切正常。 一旦将外键添加到API项目中的任何模型类中，使用API​​就会给我带来“错误请求错误”

API.Models代码

namespace API.Models
{
    using System;
    using System.Collections.Generic;

public partial class Lead
{
    public int ID { get; set; }
    public string LeadName { get; set; }
    public Nullable<decimal> AssignedTo { get; set; }
    public virtual User User1 { get; set; } //User is another entity in API.Models
    }
}

APP。型号代码

namespace APP.Models
{
    using System;
    using System.Collections.Generic;

public partial class Lead
{
    public int ID { get; set; }
    public string LeadName { get; set; }
    public Nullable<decimal> AssignedTo { get; set; }
    public virtual User User1 { get; set; }  //User is another entity in APP.Models
    }
}

API代码

namespace APIProject.API
{
    public class IssueLogController : ApiController
    {
        CRMEntities db = new CRMEntities();

        [ResponseType(typeof(Lead))]
        public async Task<IHttpActionResult> PostLead(Lead lead)
        {
            if (!ModelState.IsValid)
            {
                return BadRequest(ModelState);
            }

            db.Lead.Add(lead);

            try
            {
                await db.SaveChangesAsync();
            }
            catch (DbUpdateException)
            {
                if (LeadExists(lead.ID))
                {
                    return Conflict();
                }
                else
                {
                    throw;
                }
            }
            return CreatedAtRoute("DefaultApi", new { id = lead.ID }, lead);
        }

    }
}

Xamarin.Forms代码

Lead lead = new Lead();
            lead.LeadName = txtLead.Text.Trim();

        var uri = Constants.URL + "Lead/PostLead/";
        HttpClient client = new HttpClient(new NativeMessageHandler());

        var s = new JsonSerializerSettings { DateFormatHandling = DateFormatHandling.MicrosoftDateFormat };
        var json = JsonConvert.SerializeObject(lead, s);
        var content = new StringContent(json, Encoding.UTF8, "application/json");

        var response = await client.PostAsync(uri, content);
        if (response.IsSuccessStatusCode)
        {
            await DisplayAlert("Message", "Your Lead has been recorded.", "OK");
        }

有解决这个问题的想法吗？

Answer 1

正如@Gerald在上面的评论中提到的，这是我在API代码中所做的操作以找出错误-

 if (!ModelState.IsValid)
        {
            StringBuilder sb = new StringBuilder();
            foreach (var state in ModelState)
            {
                foreach (var error in state.Value.Errors)
                {
                    sb.AppendLine(error.ErrorMessage);
                }
            }
            t_app_issueLog.ID = 1;
            t_app_issueLog.Problem = sb.ToString();
            return CreatedAtRoute("DefaultApi", new { id = lead.ID }, lead);
            //return BadRequest(ModelState);
        }