Book Image

Mastering Windows Presentation Foundation

By : Sheridan Yuen
Book Image

Mastering Windows Presentation Foundation

By: Sheridan Yuen

Overview of this book

Windows Presentation Foundation is rich in possibilities when it comes to delivering an excellent user experience. This book will show you how to build professional-grade applications that look great and work smoothly. We start by providing you with a foundation of knowledge to improve your workflow – this includes teaching you how to build the base layer of the application, which will support all that comes after it. We’ll also cover the useful details of data binding. Next, we cover the user interface and show you how to get the most out of the built-in and custom WPF controls. The final section of the book demonstrates ways to polish your applications, from adding practical animations and data validation to improving application performance. The book ends with a tutorial on how to deploy your applications and outlines potential ways to apply your new-found knowledge so you can put it to use right away.
Table of Contents (19 chapters)
Mastering Windows Presentation Foundation
About the Author
About the Reviewer
Customer Feedback

Avoiding UI-based validation errors

In the last example from the previous section, we data bound the whole Validation.Errors collection to a tooltip in the error template for our textbox. We also data bound our own Errors collection from our base class to the items control above the form fields.

Our Errors collection can display all of the errors for all of the properties in each data model. However, the Validation.Errors collection has access to UI-based validation errors that never make it back to the View Models. Take a look at the following example:

The UI-based validation error says Value '0t' could not be converted and that explains why the View Models never see this error. The type of value expected in the data bound property is decimal, but an unconvertible value has been entered. Therefore, the input value cannot be converted to a decimal and so, the data bound value is never updated.

However, the Validation.Errors collection is a UI element and each data bound control has its own...