Asp.net Angular 8 httpclient如何发送JSON头

我正在尝试使用angular 8 HttpClient向ASP.net核心后端发送JSON，代码如下：

import { HttpClient, HttpHeaders} from '@angular/common/http';

import { User } from '@/_models';

    login(username, password) {
        return this.http.post<any>(`https://${config.apiUrl}/api/User/LoginUser`,
                JSON.stringify({
                    "username": username,
                    "password": password 
                })
        ).pipe(map(user => {
            // store user details and jwt token in local storage to keep user logged in between page refreshes
            localStorage.setItem('currentUser', JSON.stringify(user));
            console.log(user);
            this.currentUserSubject.next(user);
            return user;
        }));
    }
}

正在发送请求

请求头包括：

POST /api/User/LoginUser HTTP/1.1
Host: (Checked_and_correct_API_URL)
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:71.0) Gecko/20100101 Firefox/71.0
Accept: application/json, text/plain, */*
Accept-Language: en-US,en;q=0.5
Accept-Encoding: gzip, deflate, br
Referer: http://localhost:8080/login
Content-Type: text/plain
Content-Length: 49
Origin: http://localhost:8080
DNT: 1
Connection: keep-alive

HTTP/2.0 415 Unsupported Media Type
content-type: application/problem+json; charset=utf-8
server: Microsoft-IIS/10.0
x-powered-by: ASP.NET
date: Thu, 19 Dec 2019 13:10:01 GMT
content-length: 147
X-Firefox-Spdy: h2

响应标题为：

POST /api/User/LoginUser HTTP/1.1
Host: (Checked_and_correct_API_URL)
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:71.0) Gecko/20100101 Firefox/71.0
Accept: application/json, text/plain, */*
Accept-Language: en-US,en;q=0.5
Accept-Encoding: gzip, deflate, br
Referer: http://localhost:8080/login
Content-Type: text/plain
Content-Length: 49
Origin: http://localhost:8080
DNT: 1
Connection: keep-alive

HTTP/2.0 415 Unsupported Media Type
content-type: application/problem+json; charset=utf-8
server: Microsoft-IIS/10.0
x-powered-by: ASP.NET
date: Thu, 19 Dec 2019 13:10:01 GMT
content-length: 147
X-Firefox-Spdy: h2

发送的参数为：

{"username":"jeboimarc2","password":"KUTminor1!"}

这也是正确的

---

有人能告诉我为什么出现不支持的媒体类型错误吗？提前感谢。

传递原始json数据，不要将其转换为字符串

试着这样做：

return this.http.post<any>(`https://${config.apiUrl}/api/User/LoginUser`,{"username": username, "password": password })

返回此.http.post（`https://${config.apirl}/api/User/logiuser`，{“用户名”：用户名，“密码”：密码}）

首先，感谢您的快速回答，很抱歉，假期的事情都发生了，我无法回到这里。现在我在发送JSON时得到了一个405（不允许使用方法）。不过，我认为这是由于我运行的网络浏览器，今天下午我将尝试另一个