this._http.post<any>(this.baseUrl + 'api/Tasks/AddTask', { id: 1, title: 'dddd', description: 'vvvv' }).subscribe(
      (res) => console.log(res),
      (err) => console.log(err)
    );

[HttpPost("[action]")]
public JsonResult AddTask(TaskDTO task)
{
    return Json(new { result = "ok" });
}

public class TaskDTO
    {
        public int id { get; set; }

        public string title { get; set; }

        public string description { get; set; }
    }