else {
                    dtCustomers.Clear();
                    daCustomers.Fill(dsNorthwind, "CustomerOrders");
                }
            }
            catch(SqlCeException e) {
                // Error handling mechanism
                //
                System.Windows.Forms.Cursor.Current = System.Windows.Forms.Cursors.Default;
                NorthwindData.ShowErrors(e);
                return;
            }
            catch(Exception e) {
                // Error handling mechanism
                //
                System.Windows.Forms.Cursor.Current = System.Windows.Forms.Cursors.Default;
                MessageBox.Show(e.Message, "Northwind");
                return;
            }

            selectedCustomerID = comboBoxCustomers.SelectedValue.ToString();
            RefreshOrders();
            System.Windows.Forms.Cursor.Current = System.Windows.Forms.Cursors.Default;
        }


        private void ClearOrders() {
            listViewOrders.Items.Clear();
        }


        private void ClearProducts() {
            listViewProducts.Items.Clear();
        }
		

        // Refreshes the Products ListView
        //
        private void RefreshProducts() {
            SqlCeCommand cmdProducts = null;
            SqlCeDataReader drProducts = null;
            SqlCeConnection cnNorthwind = NorthwindData.GetInstance().NorthwindConnection;
            ListViewItem listViewItem = null;
            string item;
            string sql;

            if (0 == listViewOrders.SelectedIndices.Count) {
                return;
            }

            item = listViewOrders.FocusedItem.Text;
            if (0 == item.Length) {
                return;
            }

            sql = @"SELECT P.ProductName, O.UnitPrice, O.Quantity, O.Discount " + 
                  @"FROM ""Order Details"" AS O " + 
                  @"INNER JOIN Products AS P " + 
                  @"ON O.ProductID = P.ProductID " +
                  @"WHERE OrderID = " + item + " " +
                  @"ORDER BY P.ProductName";

            try {
                cmdProducts = new SqlCeCommand(sql, cnNorthwind);
                drProducts = cmdProducts.ExecuteReader();

                int fieldCount = drProducts.FieldCount;

                while(drProducts.Read()) {
                    listViewItem = new ListViewItem("");

                    for (int i = 0; i < fieldCount; ++i) {
                        if (!drProducts.IsDBNull(i)) {
                            item = drProducts.GetValue(i).ToString();
                        }
                        else {
                            item = "";
                        }

                        if (0 == i) {
                            listViewItem.Text = item;
                        }
                        else {
                            listViewItem.SubItems.Add(item);
                        }
                    }

                    listViewProducts.Items.Add(listViewItem);
                }
            }
            catch(SqlCeException e) {
                // Error handling mechanism
                //
                System.Windows.Forms.Cursor.Current = System.Windows.Forms.Cursors.Default;
                NorthwindData.ShowErrors(e);
                return;
            }
            catch(Exception e) {
                // Error handling mechanism
                //
                System.Windows.Forms.Cursor.Current = System.Windows.Forms.Cursors.Default;
                MessageBox.Show(e.Message, "Northwind");
                return;
            }
            finally {
                drProducts.Close();
            }
        }


        // Refreshes the Orders ListView
        //
        private void RefreshOrders() {

            SqlCeCommand cmdOrders = null;
            SqlCeDataReader drOrders = null;
            SqlCeConnection cnNorthwind = NorthwindData.GetInstance().NorthwindConnection;
            ListViewItem listViewItem = null;
            string item;
            string sql;

            sql = @"SELECT O.OrderID, O.OrderDate, O.RequiredDate, O.ShippedDate, S.CompanyName " +
                  @"FROM Orders AS O " +
                  @"INNER JOIN Shippers AS S " +
                  @"ON O.ShipVia = S.ShipperID " +
                  @"WHERE CustomerID = '" + selectedCustomerID + "' " + 
                  @"ORDER BY O.OrderDate DESC";

            try {
                cmdOrders = new SqlCeCommand(sql, cnNorthwind);
                drOrders = cmdOrders.ExecuteReader();

                int fieldCount = drOrders.FieldCount;
                while(drOrders.Read()) {
                    listViewItem = new ListViewItem("");

                    for (int i = 0; i < fieldCount; ++i) {
                        if (!drOrders.IsDBNull(i)) {
                            if ("DateTime" == drOrders.GetDataTypeName(i)) {
                                item = drOrders.GetDateTime(i).ToShortDateString();
                            }
                            else {
                                item = drOrders.GetValue(i).ToString();
                            }
                        }
                        else {
                            item = "";
                        }

                        if (0 == i) {
                            listViewItem.Text = item;
                        }
                        else {
                            listViewItem.SubItems.Add(item);
                        }
                    }

                    listViewOrders.Items.Add(listViewItem);
                }
            }
            catch(SqlCeException e) {
                // Error handling mechanism
                NorthwindData.ShowErrors(e);
                return;
            }
            catch(Exception e) {
                // Error handling mechanism
                MessageBox.Show(e.Message, "Northwind");
                return;
            }
            finally {
                drOrders.Close();
            }
        }


        // Sets the selectedCustomerID for the SQL query inside the RefreshOrders method.
        //
        private void comboBoxCustomers_SelectedIndexChanged(object sender, System.EventArgs e) {
            
            // Note, the selectedCustomerID cannot be empty, which is by design.
            //
            if (!selectedCustomerID.Equals(comboBoxCustomers.SelectedValue) && 0 < selectedCustomerID.Length) {

                selectedCustomerID = comboBoxCustomers.SelectedValue.ToString();

                refreshOrders = true;

                ClearOrders();
                RefreshOrders();
                ClearProducts();

                refreshOrders = false;
            }
        }


        private void listViewOrders_SelectedIndexChanged(object sender, System.EventArgs e) {
            if (!refreshOrders) {
                ClearProducts();
                RefreshProducts();
            }
        }
    }
}