private async void ReloadSpentPerCategoryList() { var categoriesHelper = new TransactionsHelper(new TransactionsRepository()); try { var transactions = await categoriesHelper .GetAmountSpentPerCategory(Domain.Constants.Constants.TestUserId); var listViewItems = GetSpentPerCategoryListViewItems(transactions); spentPerCategoryList.Items.Clear(); spentPerCategoryList.Items.AddRange(listViewItems); } catch (ArgumentNullException ex) { Error.ShowDialog(ex.Message); } }