inventory.cs

采用vc#.net和sqlce实现智能手机端和服务器数据交换

            this.dvInventory.RowFilter = String.Empty;
            if (0 == this.dvInventory.Count)
            {
                MessageBox.Show("No inventory", "IBuySpy Delivery");
                return false;
            }

            this.dvInventory.RowFilter = String.Format("CategoryID = '{0}'", this.categoryID);

            try
            {
                /// Update the user interface controls.
                ///
                UpdateControls();
            }
            catch(Exception e)
            {
                MessageBox.Show(e.Message, "IBuySpy Delivery");
            }

            return true;
        }

        /// Update the user interface controls.
        ///
        internal void UpdateControls()
        {
            DataRowView row         = null;
            int         maxQuantity = 0;

			/// If there is no order selected, the user navigated to the Inventory control by using the menu.
			/// In this case, the user cannot add a product because there is no order to which a product can be added.
			/// Disable the Add Product and Cancel buttons.
			///
            if (-1 == this.orderID)
            {
                this.btnAddProduct.Enabled = false;
                this.btnCancel.Enabled     = false;
            }
			/// Otherwise, there is an order to which the product can be added; enable both the Add Product and
			/// Cancel buttons.
			///
            else
            {
                this.btnAddProduct.Enabled = true;
                this.btnCancel.Enabled     = true;
            }

			/// If there is no inventory, the Product combo box is disabled, and no product image is displayed.
			///
            if (0 == this.dvInventory.Count)
            {
                this.productID                = -1;
                this.cboProduct.Enabled       = false;
                this.pboProductImage.Image    = null;
            }
			/// Otherwise, enable the product combo box (so users can select products) and update the
			/// maximum quantity of the selected product.
			///
            else
            {
                this.cboProduct.Enabled       = true;

                row = (DataRowView)BindingContext[dvInventory].Current;
                maxQuantity = Convert.ToInt32(row["Quantity"]);
            }

			/// Update the max quantity numeric control.
			///
            UpdateMaxQuantity(maxQuantity);

			/// Refresh the user interface.
			///
            Update();
        }

        /// Update the subtotal.
        ///
        private void UpdateSubTotal()
        {
            decimal subTotal = 0;

            if (0 != this.lblPriceValue.Text.Length)
            {
                decimal unitCost = Convert.ToDecimal(this.lblPriceValue.Text);

                /// Calculate the subtotal by multiplying the unit cost by the quantity.
                ///
                subTotal = this.numQuantity.Value * unitCost;
            }

            this.lblSubTotalValue.Text = subTotal.ToString("C");
        }

		/// Update the max quantity numeric control.
		///
        private void UpdateMaxQuantity(int maxQuantity)
        {
			/// If there are one or more products, enable the numeric control, set the minimum value to 1 (the
			/// user cannot add less than one product), and set the maximum value to the max quantity.
			///
            if (0 < maxQuantity)
            {
                this.numQuantity.Enabled = true;
                this.numQuantity.Minimum = 1;
                this.numQuantity.Maximum = maxQuantity;
                this.numQuantity.Value   = 1;
                this.numQuantity.Text    = "1";
            }
			/// Otherwise, disable the numeric control and set all properties to 0.
			///
            else
            {
                this.numQuantity.Minimum = 0;
				this.numQuantity.Maximum = 0;
                this.numQuantity.Value   = 0;
                this.numQuantity.Text    = "0";
                this.numQuantity.Enabled = false;
            }
        }

		/// Load the product image. The image name is retrieved from the database. The actual image file
		/// is on disk on the device.
		///
        private void LoadProductImage(string productImage)
        {
            try
            {
                this.pboProductImage.Image = new Bitmap(this.dataIBuySpy.ProgramPath + @"\" + productImage);
            }
            catch(Exception e)
            {
                MessageBox.Show("Load product photo: " + e.Message, "IBuySpy Delivery");
            }
        }

		/// The category combo box allows users to change the category of products that are displayed. Changing the category filters the 
		/// inventory in the products combo box accordingly.
		///
        private void cboCategory_SelectedIndexChanged(object sender, System.EventArgs e)
        {
            if (0 <= this.cboCategory.SelectedIndex && 
                this.categoryID != Convert.ToInt32(this.cboCategory.SelectedValue))
            {
                this.categoryID = Convert.ToInt32(this.cboCategory.SelectedValue);
                RefreshInventory();
            }
        }

		/// The product combo box allows the user to select different products to view (and optionally add to the
		/// current order). Selecting a specific product updates user
		/// interface controls for quantity, subtotal, and product image. The user interface control for price is automatically updated because it is bound
		/// to the Inventory data view.
		///
        private void cboProduct_SelectedIndexChanged(object sender, System.EventArgs e)
        {
            if (0 <= this.cboProduct.SelectedIndex &&
                this.productID != Convert.ToInt32(this.cboProduct.SelectedValue))
            {
                this.productID = Convert.ToInt32(this.cboProduct.SelectedValue);

                /// Set the current binding position.
                ///
                BindingContext[dvInventory].Position = this.cboProduct.SelectedIndex;

                /// Get the current row.
                ///
                DataRowView row = (DataRowView)BindingContext[dvInventory].Current;

                UpdateMaxQuantity(Convert.ToInt32(row["Quantity"]));
                UpdateSubTotal();
                LoadProductImage(row["ProductImage"].ToString());
            }
        }

		/// If the user changes the value of the quantity numeric control using the control arrows,
		/// update the subtotal accordingly.
		///
        private void numQuantity_ValueChanged(object sender, System.EventArgs e)
        {
            UpdateSubTotal();
        }

		/// If the user changes the value of the quantity numeric control by typing in a new number,
		/// update the subtotal accordingly.
		///
        private void numQuantity_TextChanged(object sender, System.EventArgs e)
        {
            int quantity;

            try
            {
                quantity = Convert.ToInt32(this.numQuantity.Text);
            }
            catch
            {
                quantity = 0;
            }

            if (this.numQuantity.Minimum > quantity || 
                this.numQuantity.Maximum < quantity)
            {
                MessageBox.Show(String.Format(@"The number you have entered is invalid. Please enter a valid number ({0} - {1}).", this.numQuantity.Minimum, this.numQuantity.Maximum), 
                                "IBuySpy Delivery");

                this.numQuantity.Text  = this.numQuantity.Minimum.ToString();
                this.numQuantity.Value = this.numQuantity.Minimum;
            }

            UpdateSubTotal();
        }

		/// Add the selected product to the current order.
		///
        private void btnAddProduct_Click(object sender, System.EventArgs e)
        {
            int remainingQuantity = 0;
            int productID;
            int quantity;
            decimal unitCost;
            DataRowView row = null;

            /// If there is no inventory, return.
            ///
            if (0 == this.dvInventory.Count)
            {
                return;
            }

            try
            {
                quantity = Convert.ToInt32(this.numQuantity.Text);
            }
            catch
            {
                quantity = 0;
            }

            /// Validate the quantity number.
            ///
            if (this.numQuantity.Minimum > quantity || 
                this.numQuantity.Maximum < quantity)
            {
                MessageBox.Show(String.Format(@"The number you have entered is invalid. Please enter a valid number ({0} - {1}).", this.numQuantity.Minimum, this.numQuantity.Maximum), 
                                "IBuySpy Delivery");

                this.numQuantity.Text  = this.numQuantity.Minimum.ToString();
                this.numQuantity.Value = this.numQuantity.Minimum;

                UpdateSubTotal();

                return;
            }

            /// Get the current row.
            ///
            row = (DataRowView)BindingContext[this.dvInventory].Current;

            productID = Convert.ToInt32(row["ProductID"]);
            quantity  = Convert.ToInt32(this.numQuantity.Value);
            unitCost  = Convert.ToDecimal(row["UnitCost"]);

            try
            {
				/// Add the selected product to the dataset.
				///
                this.dataIBuySpy.AddProduct(this.orderID, productID, row["ModelName"].ToString(), quantity, unitCost);

				/// Calculate the remaining quantity after the product has been added.
				///
                remainingQuantity = Convert.ToInt32(row["Quantity"]) - quantity;

				/// If there are one or more of the selected products remaining, update the quantity of the selected
				/// product in the dataset.
				///
                if (0 < remainingQuantity)
                {
                    row["Quantity"] = remainingQuantity;
                }
                /// Otherwise, delete the selected product from the dataset.
                ///
                else
                {
                    row.Delete();
                }
            }
            catch(SqlCeException err)
            {
                IBuySpyData.ShowErrors(err);
            }
            catch(Exception err)
            {
                MessageBox.Show("Add product: " + err.Message, "IBuySpy Delivery");
            }

            UpdateMaxQuantity(remainingQuantity);

            /// Go back to the Orders control.
            ///
            OnViewOrders(this, new OrderEventArgs());
        }

        /// Go back to the Orders control.
        ///
        private void btnCancel_Click(object sender, System.EventArgs e)
        {
            OnViewOrders(this, new OrderEventArgs());
        }
	}
}