Angular 2 http post params and body

The 2nd parameter of http.post is the body of the message, ie the payload and not the url search parameters. Pass data in that parameter.

From the documentation

post(url: string, body: any, options?: RequestOptionsArgs) : Observable<Response

    public post(cmd: string, data: object): Observable<any> {

        const params = new URLSearchParams();
        params.set('cmd', cmd);

        const options = new RequestOptions({
          headers: this.getAuthorizedHeaders(),
          responseType: ResponseContentType.Json,
          params: params,
          withCredentials: false
        });

        console.log('Options: ' + JSON.stringify(options));

        return this.http.post(this.BASE_URL, data, options)
          .map(this.handleData)
          .catch(this.handleError);
      }

---

Edit

You should also check out the 1st parameter (BASE_URL). It must contain the complete url (minus query string) that you want to reach. I mention in due to the name you gave it and I can only guess what the value currently is (maybe just the domain?).

Also there is no need to call JSON.stringify on the data/payload that is sent in the http body.

If you still can't reach your end point look in the browser's network activity in the development console to see what is being sent. You can then further determine if the correct end point is being called wit the correct header and body. If it appears that is correct then use POSTMAN or Fiddler or something similar to see if you can hit your endpoint that way (outside of Angular).

And it works, thanks @trichetriche. The problem was in my RequestOptions, apparently, you can not pass params or body to the RequestOptions while using the post. Removing one of them gives me an error, removing both and it works. Still no final solution to my problem, but I now have something to work with. Final working code.

public post(cmd: string, data: string): Observable<any> {

    const options = new RequestOptions({
      headers: this.getAuthorizedHeaders(),
      responseType: ResponseContentType.Json,
      withCredentials: false
    });

    console.log('Options: ' + JSON.stringify(options));

    return this.http.post(this.BASE_URL, JSON.stringify({
      cmd: cmd,
      data: data}), options)
      .map(this.handleData)
      .catch(this.handleError);
  }

Let said our backend looks like this:

public async Task<IActionResult> Post([FromBody] IList<UserRol> roles, string notes) {
}

We have a HttpService like this:

    post<T>(url: string, body: any, headers?: HttpHeaders, params?: HttpParams): Observable<T> {
        return this.http.post<T>(url, body, { headers: headers, params});
    }

Following is how we can pass the body and the notes as parameter: // how to call it

const headers: HttpHeaders = new HttpHeaders({
    'Authorization': `Bearer XXXXXXXXXXXXXXXXXXXXXXXXXXX`
});

const bodyData = this.getBodyData(); // get whatever we want to send as body

let params: HttpParams = new HttpParams();
params = params.set('notes', 'Some notes to send');

this.httpService.post<any>(url, bodyData, headers, params);

It worked for me (using angular 7^), I hope is useful for somebody.