415 (Unsupported Media Type) angular 4 Post

In my case the 415 error was caused because I was calling JSON.stringify(obj) when there was no need for it. I read somewhere that post method will stringify the body parameter as needed

So instead of this:

this._http
.post(
    this.baseUrl + 'home/Save', 
    JSON.stringify(this.obj),
    this.headers
 )

I changed it to this:

this._http
.post(
    this.baseUrl + 'home/Save', 
    this.obj, // << no need to stringify 
    this.headers
)

Here is my actual working code

@Injectable()
export class ParkingService {
  constructor(private http: HttpClient) { }

  create(parking: Parking) {
    const requestUrl = environment.apiUrl + 'parking' ;
    const headerOptions = new HttpHeaders();

    headerOptions.set('Content-Type', 'application/json');
    return this.http.post(requestUrl, parking, {headers: headerOptions}) ;
  }
}

This happened to me even after enabling and configuring CORS on the .NET core web api

You need to change the below line

  headers = { headers: new Headers({ 'Content-Type': 'application/json' }) 
      };

to

headers={
    headers: new HttpHeaders({
        'Content-Type': 'application/json'
    })
}