A Dependency Property is a property whose value depends on the external sources, such as animation, data binding, styles, or visual tree inheritance. Not only this, but a Dependency Property also has the built-in feature of providing notification when the property has changed, data binding and styling.

How does dependency property work?

To summarize,

1. Dependency Property System holds a collection of all DependencyProperty with its corresponding ownerType.
2. Each instance of a DependencyObject holds a collection of all individual DependencyProperty that has been changed either through animation or programmatically.

What is a dependency object?

Remarks. The DependencyObject class enables Windows Presentation Foundation (WPF) property system services on its many derived classes. The property system’s primary function is to compute the values of properties, and to provide system notification about values that have changed.

What is the difference between property and dependency property?

Why We Need Dependency Properties CLR properties can directly read/write from the private member of a class by using getter and setter. In contrast, dependency properties are not stored in local object. Dependency properties are stored in a dictionary of key/value pairs which is provided by the DependencyObject class.

How do you create a dependency property?

Checklist for Defining a Dependency Property

1. (Optional) Create property metadata for the dependency property.
2. Register the property name with the property system, specifying an owner type and the type of the property value.
3. Define a DependencyProperty identifier as a public static readonly field on the owner type.

What is a dependency property?

A Dependency Property is a property whose value depends on the external sources, such as animation, data binding, styles, or visual tree inheritance. Not only this, but a Dependency Property also has the built-in feature of providing notification when the property has changed, data binding and styling.

How does dependency property save memory?

As long as a Dependency Property uses its default state (which is very common), it won’t take up any additional memory since the default value will be used. The default value isn’t stored per instance, it is stored per Dependency Property and it’s set by metadata.

Why do we need dependency properties?

The main reason to create DependencyProperty is when you write you own WPF control. DependencyProperties can be used as binding source and target, and can be animated. The properties of all framework’s controls are implemented as DependencyProperty, that why you can make powerful data binding in XAML.

What is dependency property in WPF with example?

Windows Presentation Foundation (WPF) provides a set of services that can be used to extend the functionality of a type’s property. Collectively, these services are referred to as the WPF property system. A property that’s backed by the WPF property system is known as a dependency property.

What is a dependency injection in C#?

Dependency Injection (DI) is a software design pattern that allows us to develop loosely coupled code. The Dependency Injection pattern uses a builder object to initialize objects and provide the required dependencies to the object means it allows you to “inject” a dependency from outside the class.

What is dependency property in UWP?

Definition. Namespace: Windows.UI.Xaml. Represents a dependency property that is registered with the dependency property system. Dependency properties provide support for value expressions, data binding, animation, and property change notification.

What is dependency property in WPF interview?

Dependency property is a special kind of property introduced in WPF. This property helps in data binding the source and target object. Dependency property has been designed to reduce the memory footprint. These properties are static in nature.

What is CLR property?

Windows Presentation Foundation (WPF) provides a set of services that can be used to extend the functionality of a common language runtime (CLR) property. A property that is backed by the WPF property system is known as a dependency property.

How do I set default value for dependency property?

When you define a custom XAML dependency property, one of the things you do is specify the default value. You can do this by providing the default value directly: DependencyProperty. Register (“MyProperty”, propertyType, ownerType, new PropertyMetadata(defaultValue));

What attached properties?

An attached property is intended to be used as a type of global property that is settable on any object. In Windows Presentation Foundation (WPF), attached properties are typically defined as a specialized form of dependency property that does not have the conventional property “wrapper”.

Why dependency property is static in WPF?

DependencyProperty has to be static (Class level) because when we create multiple objects of the class which has that property and want to refer the default value for that property the value has to come from that static instance of DependencyProperty.