Book Image

Mastering Windows Presentation Foundation - Second Edition

By : Sheridan Yuen
Book Image

Mastering Windows Presentation Foundation - Second Edition

By: Sheridan Yuen

Overview of this book

Microsoft Windows Presentation Foundation (WPF) provides a rich set of libraries and APIs for developers to create engaging user experiences. This book features a wide range of examples, from simple to complex, to demonstrate how to develop enterprise-grade applications with WPF. This updated second edition of Mastering Windows Presentation Foundation starts by introducing the benefits of using the Model-View-View Model (MVVM) software architectural pattern with WPF, then moves on, to explain how best to debug our WPF applications. It explores application architecture, and we learn how to build the foundation layer of our applications. It then demonstrates data binding in detail, and examines the various built-in WPF controls and a variety of ways in which we can customize them to suit our requirements. We then investigate how to create custom controls, for when the built-in functionality in WPF cannot be adapted for our needs. The latter half of the book deals with polishing our applications, using practical animations, stunning visuals and responsive data validation. It then moves on, to look at improving application performance, and ends with tutorials on several methods of deploying our applications.
Table of Contents (15 chapters)

Customizing the error template

In addition to the essential Errors and HasError properties, the Validation class also declares an ErrorTemplate Attached Property of type ControlTemplate. The default template assigned to this property is responsible for defining the red rectangle that surrounds UI fields that have validation errors associated with them.

However, this property enables us to change this template and so, we are able to define how validation errors are highlighted to the application users. As this property is an Attached Property, this effectively means that we could apply a different template to be displayed for each control in the UI. However, this cannot be recommended, because it could make the application look less consistent.

This template actually uses an Adorner element to render its graphics in the adorner layer, on top of the related control in error. Therefore, in order to specify where our error visual(s) should be rendered in relation to the related control, we...