private void DeleteTestFromGroup_Click(object sender, RoutedEventArgs e) { var dg = sender as DataGrid; for (var vis = sender as Visual; vis != null; vis = VisualTreeHelper.GetParent(vis) as Visual) { if (vis is DataGridRow) { if (((System.Windows.FrameworkElement)vis).DataContext is TestViewModel) { var testId = ((DTO.TestViewModel)((System.Windows.FrameworkElement)vis).DataContext).TestId; if (testId != -1) { string answer = client.DeleteTestFromGroup(testId, dtoGroup.GroupId); if (answer == "succesfull") { main.Content = new AdminStudentGroups(client, mw, main); } } } } } }