I met the author through the Visio MVP community—a group of elite Visio experts who actively share their technical expertise with others. David Parker is a long-time Visio MVP, and we first discussed the new Diagram Validation functionality shipped with Microsoft Visio Premium 2010 almost two years before its release. As a Visio MVP, David provides input for new functionality and early feedback on features as they are developed. Diagram Validation was one of the features I worked on for Visio 2010, and David was keen to learn about its functionality.

The Visio team had heard from our customers that they spend a lot of time manually checking diagrams to find even simple problems like shapes without labels and unconnected shapes. Companies were also struggling to ensure that diagrams met certain compliancy requirements or business standards. With Diagram Validation, Visio automatically verifies properties of a diagram and displays diagramming issues. It is then easy to review the issues and fix the problems in the diagram. This automatic detection of diagramming errors is a big time saver and can greatly increase diagram quality.

Microsoft Visio Premium 2010 provides built-in validation support for Basic Flowchart, Cross-Functional Flowchart, Six Sigma, Microsoft SharePoint Workflow, and Business Process Modeling Notation (BPMN) diagrams. What intrigued David most, though, was the ability for anyone to create custom validation logic—you can specify your own custom diagram requirements, for any type of diagram, and Visio will verify these requirements for you. Moreover, once you have created custom validation logic, you can use it in all your diagrams, share it with others, distribute it within your company, or even sell it as part of a Visio solution. As most diagrams have some logical structure to them, there are many opportunities to create your own custom validation logic and extend the built-in functionality of Diagram Validation.

Although Visio 2010 has just recently been released, David is already an expert in the area of Diagram Validation. He has created new validation logic for several different diagram types, created a tool to work with validation logic in Visio, and written articles about Diagram Validation. Outside of the Visio team itself, David is probably most versed in this area of Visio 2010. It was not surprising then that David chose this area for his new book. This is David Parker’s second book—he is also the author of Visualizing Information with Microsoft Office Visio 2007.

As a technical reviewer for this book, I had a chance to read the book from cover to cover. As I read, there were a couple of key things that impressed me about its contents. First, this is more than a book about Diagram Validation; it also introduces Visio users to an assortment of new Visio 2010 features. Second, it presents a nice balance between the Visio Object Model and the Visio ShapeSheet. These two powerful tools combine to provide a unique development experience within Visio. Finally, the book provides coded examples, and even a chapter devoted to a worked example. These clear, well thought out examples are great for those who want to experiment in Visio as they read the book.

David begins this book with an overview of process management in Visio 2010. Diagram Validation is one of many features developed for business process users. In fact, business process management is a cornerstone of Microsoft Visio Premium 2010. The Visio team spent a lot of time reflecting on how we could best enhance the experience for our business process users—we added new diagram types like BPMN and SharePoint workflow, redesigned our Cross-Functionality Flowchart (CFF) support to make it easier to use, and created new support for concepts like sub-processes and Diagram Validation. Readers of this book will be introduced to a breadth of new Visio 2010 functionality, thanks to David’s considerable knowledge of Visio 2010.

David next devotes a chapter each to the Visio Object Model and the Visio ShapeSheet. Microsoft Visio is unique as a diagramming application, because of the joint power of the Visio Object Model and Visio shapes. Beginners to Visio are often surprised by the amount of data and behavioral logic that can be specified on a shape, through the ShapeSheet. For example, the way a shape interacts with other shapes and the drawing page and the way users can interact with the shape are often implemented by formulas entered in the ShapeSheet. David is well aware of the balance between creating smart shapes and writing solution code.

A similar balance exists between the Visio ShapeSheet and validation logic—the validation logic can often be made simpler if the data or logic specified on shapes is slightly more complex. Unless you write code to specify your diagram requirements, this realization is fundamental to writing validation logic for your requirements. Appropriately, the worked example for data flow model diagrams at the end of the book shows how the shape properties specified in the ShapeSheet can be leveraged when writing validation logic.

Having written a significant amount of the validation logic shipped with Visio 2010, I am familiar with the learning curve associated with writing validation logic. It was daunting, at first to ponder expressing the validation logic to check the visual correctness of a diagram based on the diagramming rules specified in the BPMN standard. Perhaps surprisingly, this task turned out to be rather straightforward—Microsoft Visio Premium 2010 shipped this BPMN validation logic and it is also written out in this book’s appendix.

To write even very complex validation logic, it is simply a matter of clearly understanding the fundamentals of Diagram Validation. This book presents these fundamentals and, through examples, shows you how to create custom validation logic. David enjoyed the challenge of writing complex diagram requirements as validation logic, and the satisfaction of having these requirements forevermore verified automatically and I hope you have a similar experience with Diagram Validation. It is very rewarding to have the ability to express diagram requirements to meet your needs, and to know these requirements will be automatically verified by Microsoft Visio Premium 2010.

Dr. Stephanie L. Horn

VISIO MVP Coordinator and Program Manager on the Visio development team