Asp.net web api 角度POST请求的标头为空

我正在开发一个Ionic 3移动应用程序，我对Angular的POST方法有问题

在登录页面中，我创建了一个表单，并尝试使用HTTP POST方法将数据发送到服务器。但在服务器.NETWebAPI中，我看到请求的头是空的

这是角边代码

  login(username, password):Observable<Object>{

    let url : string = this.apiUrl+"/login";
    let headers = new HttpHeaders();

    headers.append('Authorization', btoa(username+":"+password).toString());

    return this.http.post(url,JSON.stringify({username,password}), {headers: headers});
  }

下面是捕获请求的.NET端代码部分

protected override Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
        {
            try
            {
                var token = request.Headers.GetValues("Authorization").FirstOrDefault();
            }

            catch (Exception ex)
            {

            }

            return base.SendAsync(request, cancellationToken);
        }

通常，请求的url是localhost:8100，所以我认为服务器接受CORS

---

我该如何解决这个问题？

在Web api中，您必须根据设置路线的方式来判断是post方法还是get方法

[EnableCors(origins: "http://localhost:8100", headers: "*", methods: "*")]
[HttpPost] // Decorate post this attribute in your controller
public Response Post()
{
    return _mobileUserService.Login();
}

request = {Method: POST, RequestUri: 'http://localhost:41582/api/login', Version: 1.1, Content: System.Web.Http.WebHost.HttpControllerHandler+LazyStreamContent, Headers:
{
  Connection: keep-alive
  Accept: application/json
  Accept: text/plain
  Accept: */*
  ...

[EnableCors(origins: "http://localhost:8100", headers: "*", methods: "*")]
[HttpPost] // Decorate post this attribute in your controller
public Response Post()
{
    return _mobileUserService.Login();
}