Book Image

Windows Presentation Foundation 4.5 Cookbook

By : Pavel Yosifovich
Book Image

Windows Presentation Foundation 4.5 Cookbook

By: Pavel Yosifovich

Overview of this book

Windows Presentation Foundation (WPF) provides developers with a unified programming model for building rich Windows smart client user experiences that incorporate UI, media, and documents.WPF has become the leading technology for developing rich client applications on the Windows platform, packed with features and capabilities. However, WPF is big; in fact, it's huge, causing a steep learning curve for the beginner and even for those already using some WPF features.Windows Presentation Foundation 4.5 Cookbook provides clear recipes for common WPF tasks. It includes detailed explanations and code examples for customizing and enhancing the basic scenarios, while gaining a deep understanding of WPF mechanics and capabilities.WPF is different and requires a different mind-set and approach. This book provides recipes and insights not only in its design but also its practical implementation details.Starting from the foundations of WPF, such as dependency properties and XAML, the book touches on all major WPF aspects, such as controls and layout, resources, and digs deep into its unprecedented data binding capabilities.The book shows data and control templates in action, which allow full customizations of displayed data and controls in a declarative way. Supported by styles and resources makes data binding all the more powerful. The Model View View-Model pattern is presented as an effective way of maximizing decoupling of components, while providing an elegant way of expanding applications while maintaining a tight grip on complexity.The later parts discuss custom elements and controls ñ the ultimate customization mechanism, and looks at multithreading issues, and how .NET 4.5 task parallelism features can enhance application performance.
Table of Contents (18 chapters)
Windows Presentation Foundation 4.5 Cookbook
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
Index

Creating an undo/redo system


Up until now we have been executing commands by using the RelayCommand helper class. This allows us to separate the command implementation (in the ViewModel) from the view without creating a separate class for each command. Many applications need to not only execute commands, but also to undo already executed commands; the canonical case may be a text editor, but it can be anything. Let's see one way to build an undo/redo system that integrates with the commands infrastructure we've seen so far.

Getting ready

We'll use two projects we've already created. The first is CH07.CookbookMVVM, our MVVM framework (which we'll expand), and there is also CH07.BlogReader to demonstrate adding undo/redo capabilities.

How to do it...

We'll add undo/redo capabilities to the blog reader application, both at the MVVM framework level and application level:

  1. Add a new interface to the CH07.CookbookMVVM project and name it IUndoCommand. Define it as follows:

    public interface IUndoCommand...