public void modifyCategory(object sender, RoutedEventArgs arg) { if (CatagoryList.SelectedItem == null) { MessageBox.Show("Please select Catagory to change"); return; } if (ModifyCategory.Text == "") { MessageBox.Show("Cannot add blank name"); return; } ClientRequests.modifyCategory((String)CatagoryList.SelectedItem, ModifyCategory.Text); filter = ClientRequests.getFilters(); CatagoryList.ItemsSource = filter.categories.Select(x => x.category); }