private void LstViewTravelPackages_SelectedIndexChanged(object sender, EventArgs e)
        {
            TravelPackageDB packageDetails = new TravelPackageDB();

            packageDetails.ShowSelectedOrder(lstViewTravelPackages, lblPackageID, lblPackageName, lblStartDate, lblEndDate, lblDescription, lblBasePrice, lblCommission);
            ShowLabels();
            btnEditPackage.Enabled   = true;
            btnDeletePackage.Enabled = true;

            int            packageId       = Convert.ToInt32(lblPackageID.Text);
            List <Package> packageProducts = TravelPackageDB.GetPackageProducts(lstProducts, packageId);
        }
        // lists all products in package and available products not yet added
        public AddProductForm(int packageId, string packageName)
        {
            InitializeComponent();

            lblPackageName.Text = packageName;
            lblPackageId.Text   = Convert.ToString(packageId);

            if (lstProducts.Items != null)
            {
                List <Package> packageProducts = TravelPackageDB.GetPackageProducts(lstProducts, packageId);
                List <Package> showProducts    = TravelPackageDB.ShowAllProducts(lstAllProducts, packageId);
            }
        }
        // remove product from package
        private void BtnRemoveProduct_Click(object sender, EventArgs e)
        {
            if (lstProducts.SelectedItem == null)
            {
                MessageBox.Show("A product must be selected to remove");
            }
            else
            {
                int packageId = Convert.ToInt32(lblPackageId.Text);
                int productId = Convert.ToInt32(lblProductId.Text);

                TravelPackageDB removeProduct = new TravelPackageDB();
                removeProduct.RemovePackageProduct(productId, packageId);
                List <Package> refreshProducts = TravelPackageDB.GetPackageProducts(lstProducts, packageId);
                List <Package> showProducts    = TravelPackageDB.ShowAllProducts(lstAllProducts, packageId);
            }
        }
        // add product to package
        private void BtnAdd_Click(object sender, EventArgs e)
        {
            if (lstAllProducts.SelectedItem == null)
            {
                MessageBox.Show("A product must be selected to add");
            }
            else
            {
                int packageId = Convert.ToInt32(lblPackageId.Text);
                int productId = Convert.ToInt32(lblListNewProd.Text);

                TravelPackageDB getProdSupplierId = new TravelPackageDB();
                int             supplierId        = getProdSupplierId.GetSupplierId(productId);
                getProdSupplierId.AddPackageToProd(Convert.ToInt32(lblPackageId.Text), supplierId);
                List <Package> refreshProducts = TravelPackageDB.GetPackageProducts(lstProducts, packageId);
                List <Package> showProducts    = TravelPackageDB.ShowAllProducts(lstAllProducts, packageId);
            }
        }