private void OrderDatesButton_Click(object sender, EventArgs e) { OrdersResultTextBox.Text = ""; SqlOperations.DisplayFormattedSql = true; SqlOperations.OnShowFormattedStatementEvent += SqlOperations_OnShowFormattedStatementEvent; var sb = new StringBuilder(); sb.AppendLine("Results"); sb.AppendLine(""); var orderDates = new List <string>() { "10-17-2014", "06/11/2015", "10/30/2015" }; var orders = SqlOperations.ExampleOrderDates(orderDates); var groupedOrderItems = orders .GroupBy(ord => ord.OrderDate) .Select(ord => new OrderItem { OrderDateTime = ord.Key, OrderList = ord.ToList() }) .ToList(); foreach (var groupedOrderItem in groupedOrderItems) { sb.AppendLine($"{groupedOrderItem.OrderDateTime.Value:d} - {groupedOrderItem.OrderList.Count}"); } MessageBox.Show(sb.ToString()); SqlOperations.OnShowFormattedStatementEvent -= SqlOperations_OnShowFormattedStatementEvent; SqlOperations.DisplayFormattedSql = false; }