protected void btnApply_Click(object sender, EventArgs e) { clsOrderLineCollection Lines = new clsOrderLineCollection(); try { Lines.FilterByOrderId(Convert.ToInt32(txtFilter.Text)); lstOrderLineList.DataSource = Lines.OrderLineList; lstOrderLineList.DataValueField = "OrderLineId"; lstOrderLineList.DataBind(); } catch { lblError.Text = "Please Insert an Order Id"; } }