private async void EditPlanet_ButtonClick(object sender, RoutedEventArgs e)
        {
            if (DGrid1.SelectedItem as Planet != null)
            {
                PlanetEditingWindow win = new PlanetEditingWindow(DGrid1.SelectedItem as Planet);
                if (win.ShowDialog() == true)
                {
                    RestService restService = new RestService("https://webapi20210607153930.azurewebsites.net/", "/Planet", token);

                    if (win.Planet.PlanetID == null || win.Planet.PlanetID == string.Empty)
                    {
                        win.Planet.PlanetID = Guid.NewGuid().ToString();
                    }

                    restService.Put <string, Planet>((DGrid1.SelectedItem as Planet).PlanetID, win.Planet);
                    MessageBox.Show("Product updated in the database");

                    await this.GetStarNames();

                    await this.RefreshPlanetList();
                }
                else
                {
                    MessageBox.Show("Modifying selected product was not successful");
                }
            }
            else
            {
                MessageBox.Show("Could not modify selected product.");
            }
        }
        private async void AddNewPlanet_ButtonClick(object sender, RoutedEventArgs e)
        {
            PlanetEditingWindow win = new PlanetEditingWindow();

            if (win.ShowDialog() == true)
            {
                RestService restService = new RestService("https://webapi20210607153930.azurewebsites.net/", "/Planet", token);

                if (win.Planet.PlanetID == null || win.Planet.PlanetID == string.Empty)
                {
                    win.Planet.PlanetID = Guid.NewGuid().ToString();
                }
                if (CustomerCbox.SelectedItem as Star != null)
                {
                    win.Planet.StarID = (CustomerCbox.SelectedItem as Star).StarID;
                }

                restService.Post <Planet>(win.Planet);
                MessageBox.Show("planet added to database");

                await this.GetStarNames();

                await this.RefreshPlanetList();
            }
            else
            {
                MessageBox.Show("Adding new planet failed");
            }
        }