public async Task <ActionResult <FitnessHistoryDto> > addWorkout([FromBody] FitnessHistoryDto fitnessHistoryDto)
        {
            try
            {
                string username = User.Claims.FirstOrDefault(c => c.Type == ClaimTypes.Name)?.Value ?? "";
                User   user     = _context.User.Where(d => username.ToLower() == d.U_Name.ToLower()).FirstOrDefault();
                Kunde  kunde    = _context.Kunde.Find(user.U_Kunde_Nr);

                Fitness_history history = new Fitness_history
                {
                    FH_Date                = Encoding.ASCII.GetBytes(fitnessHistoryDto.Date),
                    FH_Bewertung           = Encoding.ASCII.GetBytes(fitnessHistoryDto.Bewertung),
                    FH_Kunde_Nr            = long.Parse("" + kunde.K_Nr),
                    FH_Fitness_Uebungen_Nr = fitnessHistoryDto.UebungsNr
                };
                _context.Fitness_history.Add(history);
                _context.SaveChanges();

                return(Ok(fitnessHistoryDto));
            }
            catch (DbUpdateException)
            {
                return(BadRequest());
            }
            catch (Exception)
            {
                return(StatusCode(StatusCodes.Status500InternalServerError));
            }
        }
        private async Task finishedAsync()
        {
            //string result = await DisplayPromptAsync("Workout rating","-How do you feel-",  maxLength: 1, keyboard: Keyboard.Numeric);

            try
            {
                FitnessHistoryDto w = new FitnessHistoryDto
                {
                    Date      = DateTime.Now + "",
                    Bewertung = "3.67",
                    UebungsNr = (long)Convert.ToDouble(Nr.Text)
                };
                await RestService.Instance.SendAsync <FitnessHistoryDto>(HttpMethod.Post, "fitness/addWorkout", "", w);

                NavigationPage newNavigation = new NavigationPage();
                await newNavigation.PushAsync(new DashboardPage());

                Application.Current.MainPage = new MainPage(newNavigation);
            }
            catch (Exception ex)
            {
                await DisplayAlert("Warning", "Did not save changes!", "OK");
            }
        }