Web Api 2发布-UrlHelper.Link不得返回null [英] Web Api 2 Post - UrlHelper.Link must not return null

问题描述

我有一个基本的Web API 2设置和一些基本的路由.

I have a basic web API 2 setup with some basic routing.

以下是默认路线和插入路线.当我致电该职位时，该记录已在数据库中完美创建，但是"CreatedAtRoute"调用返回500错误，指出:

Below is the default route and post for inserts. When I call the post the record is created perfectly in the database but the "CreatedAtRoute" call returns a 500 error stating:

ExceptionMessage:"UrlHelper.Link不能返回null. ExceptionType:"System.InvalidOperationException"

ExceptionMessage: "UrlHelper.Link must not return null." ExceptionType: "System.InvalidOperationException"

为什么我会收到此错误?

Why would I receive this error?

[RoutePrefix("api/casenotes")]
    public class CasenoteController : ApiController...



// POST api/Casenote
[Route("")]
[ResponseType(typeof(client_admission_casenote))]
    public async Task<IHttpActionResult> Postclient_admission_casenote   (client_admission_casenote client_admission_casenote)
{

  Request.GetRequestContext().IncludeErrorDetail = true;

  if (!ModelState.IsValid)
  {
      return BadRequest(ModelState);
  }

  db.client_admission_casenote.Add(client_admission_casenote);
  await db.SaveChangesAsync();

  return CreatedAtRoute("DefaultApi", new { id = client_admission_casenote.casenote_id }, client_admission_casenote);
    }

推荐答案

由于您正在使用属性路由.因此，您必须命名路由. [Route("api/books/{id}"，Name ="GetBookById")]

Since you are using attribute routing.. you have to name your route.. i.e. [Route("api/books/{id}", Name="GetBookById")]

，并在url.link()调用中使用路由名称

and the use the route name on your url.link() call

在此处查看详细信息.

see details here.. http://www.asp.net/web-api/overview/web-api-routing-and-actions/attribute-routing-in-web-api-2#route-names

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