var formData = new FormData();

    formData.append('ReturnFaceLandMarks', this.formViewModel.ReturnFaceLandmarks);
    formData.append('ReturnFaceId', this.formViewModel.ReturnFaceId);
    formData.append('age', this.formViewModel.age);
    formData.append('facial_hair', this.formViewModel.facial_hair);
    formData.append('gender', this.formViewModel.gender);
    formData.append('glassed', this.formViewModel.glassed);
    formData.append('head_pose',"false");
    formData.append('smile', "true");
    formData.append('file', this.formViewModel.img);

detect(data: any): Promise<any>
  {
      return this.http.post(this.serverUrl+"face/detect/", data, { headers: this.headers })
          .toPromise()
          .then(response => {
              console.log(response);
          })
          .catch(this.handleError);
  }

public IActionResult Upload(IFormFile file, [FromForm] bool smile) {
   ...
}