private void btnSearch_Click(object sender, EventArgs e) { int result = DateTime.Compare(dateTimePicker1.Value.Date, dateTimePicker2.Value.Date); if (dateTimePicker1.Value.Date <= dateTimePicker2.Value.Date && dateTimePicker1.Value.Date < DateTime.Now) { dtOrder = orderData.GetOrderBaseOnDate(dateTimePicker1.Value.Date.ToString(), dateTimePicker2.Value.Date.ToString()).Tables[0]; dgvOrder.DataSource = dtOrder; } else { MessageBox.Show("Invalid date input "); } }