WPF’s classes have a very deep inheritance hierarchy, so it can be hard to get your head wrapped around the significance of various classes and their relationships.
A handful of classes are fundamental to the inner workings of WPF and deserve a quick explanation before we get any further in the book.
One of the screens in the Windows Phone 7 app I’m currently working on (we’ll call it control–need to change their state based on a property of the parent screen (which is in turn manipulated by user input elsewhere in the app).
After mulling over several options (including using the application’s event bus and a more synchronous approach of manually modifying the controls’ properties), I decided to use Silverlight’s built-in data binding features to implement this, meaning I needed to create a Unfortunately, I spent more time than I’d care to admit trying to figure out why that wasn’t working.
For more information about dependency properties and some of the terminology and conventions used for describing them in this documentation, see Dependency properties overview. The identifier's name follows this convention: the name of the dependency property, with the string "Property" added to the end of the name. The identifier stores the information about the dependency property as it was registered, and can then be used for other operations involving the dependency property, such as calling Set Value.
Examples of dependency properties in the Windows Runtime are: Control. For example, the corresponding Dependency Property identifier for the Control. Dependency properties typically have a wrapper implementation.
We describe the implementation steps for a custom dependency property, as well as some best practices that can improve performance, usability, or versatility of the dependency property.
We assume that you have read the Dependency properties overview and that you understand dependency properties from the perspective of a consumer of existing dependency properties.
A dependency property is exposed internally as a static field that is registered with the dependency property system.This means when anyone else writes a value directly to the User Control1. This happen when you type into either the "Direct Binding" textbox or into the "Result" textbox (within the user control); both of these are bound to the User Control1.Result property and hence both will write a value that replaces the binding.This is actually a good thing, because that binding is actually circular.The user control sets its Data Context to refer to itself, so the "Path=Result" in the binding refers to the User Control1.Some of this chapter’s concepts are unique to WPF (such as logical and visual trees), but others are just extensions of concepts that should be quite familiar (such as properties).As you learn about each one, you’ll see how to apply it to a very simple piece of user interface that most programs need—an .control, the underlying binding source is updated a soon as the control loses focus.This is something you might want to prevent sometimes – a common scenario is a model dialog that provides a Cancel button to abort changes.fun topics, it’s helpful to examine some of the main concepts that WPF introduces above and beyond what . The topics in this chapter are some of the main culprits responsible for WPF’s notoriously steep learning curve.By familiarizing yourself with these concepts now, you’ll be able to approach the rest of this book (or any other WPF documentation) with confidence.