private async void btnSave_Click(object sender, RoutedEventArgs e) { var tagDataService = new TagDataService(new EntityFramework.TimetableManagerDbContext()); if (textBoxtag.Text != "") { if (isEditState) { tag.TagName = textBoxtag.Text; await tagDataService.UpdateTag(tag, tag.TagId); isEditState = false; } else { Tag newTag = new Tag { TagName = textBoxtag.Text }; await tagDataService.AddTag(newTag); } textBoxtag.Clear(); } else { MessageBox.Show("Insert a Tag!!"); } TagDataList.Clear(); _ = load(); }