The purpose of this step-by-step guide is to illustrate the process for designing and building Microsoft® Windows® DNA applications using the "Executants and Emissaries" methodology described in "Introduction to Designing and Building Windows DNA Applications." To help developers gain a better understanding of the Windows DNA application design process, and ultimately Windows DNA in general, you're encouraged to follow the various steps outlined in this document to actually build a simple Windows DNA application.
The DNA PurchaseOrder application is a very simple sample that allows users to purchase a variety of books as part of a single purchase order, similar to what you might find at your favorite online bookstore.
Figure 8. DNA PurchaseOrder application users can purchase a variety of books from the available "inventory" as part of a single purchase order, similar to the way you might purchase books from your favorite online bookstore (see Figure 9).
Users browse the store's inventory of books, adding certain items to their purchase order, and removing others. When the user is ready to checkout, the purchase order is completed by providing a destination shipping address along with a customer account number for billing, and the order is submitted. When the application receives a purchase order request, it checks the quantity on hand of each book being purchased to make sure the entire order can be fulfilled. If not, the entire order is aborted. The application also checks to make sure the customer has enough available credit to facilitate the purchase. If not, the entire order is aborted.
Figure 9. DNA PurchaseOrder application users can purchase a variety of books from the available "inventory" as part of a single purchase order, similar to the way you might purchase books from your favorite online bookstore (see Figure 8).
Beyond processing purchase orders, the DNA PurchaseOrder application also allows users to do basic purchase order, account, and inventory management functions (for example, create, modify, and destroy), although some of the account and inventory management operations require the user to be an application "Administrator."
Figure 10. Purchase order management
Figure 11. Account management
Figure 12. Inventory management
Figures 10, 11, and 12: The DNA PurchaseOrder application also allows users to perform basic purchase order, account, and inventory management functions (for example, create, modify, and destroy), although some of the account and inventory management operations require the user to be an application "Administrator."
Note While the DNA PurchaseOrder application illustrates many of the fundamental characteristics of a full-blown, production Windows DNA application, it is important to remember that the DNA PurchaseOrder application is a sample application, and is not designed to serve as a production system. The DNA PurchaseOrder application is designed merely to aid developers in gaining a clearer understanding of the Windows DNA application design and development process.