[This documentation is preliminary and is subject to change.]

Applies to: Metro style apps only

Represents an object that participates in the dependency property system. DependencyObject is the immediate base class of many important UI-related classes, such as UIElement, Geometry, FrameworkTemplate, Style, and ResourceDictionary.

Inheritance

Object

  DependencyObject

Syntax

public class DependencyObject : Object

Attributes

MarshalingBehaviorAttribute(Agile)

ThreadingAttribute(Both)

VersionAttribute(NTDDI_WIN8)

WebHostHiddenAttribute()

Members

The DependencyObject class has these types of members:

• Constructors
• Methods
• Properties

Constructors

The DependencyObject class has these constructors.

Methods

The DependencyObject class has these methods. It also inherits methods from the Object class.

Properties

The DependencyObject class has these properties.

Remarks

The DependencyObject class enables dependency property system services on its many derived classes. For more info about the dependency property concept, see Dependency properties overview.

The dependency property system's primary function is to compute the values of properties, and to provide system notification about values that have changed. Another key class that participates in the dependency property system is DependencyProperty. DependencyProperty enables the registration of dependency properties into the property system, whereas DependencyObject as a base class enables objects to use and set the dependency properties.

Here are some notable services and characteristics that DependencyObject provides or supports:

• Dependency property hosting support.
• Custom dependency property hosting support. You register a dependency property by calling the Register method and storing the method's return value as a public static property in your DependencyObject class.
• Attached property hosting support.
• Custom attached property hosting support. You register a dependency property for the attached property usage by calling the RegisterAttached method and storing the method's return value as a public static property in your class.
• Get and Set utility methods for values of any dependency properties that exist on the DependencyObject.
• Additional utility for examining metadata or property values.
• Dispatcher for advanced threading scenarios.
• Basic data binding and styling support, by enabling properties to be set as expressions to be evaluated at some later point in an object's lifetime. These concepts are explained in more detail in Dependency properties overview. See also Data binding with XAML.

Examples

This example defines a class that derives from DependencyObject, and defines an attached property along with the identifier field. The scenario for this class is that it is a service class that declares an attached property that other UI elements can set in XAML The service potentially acts on the attached property values on those UI elements at run time.

    public abstract class AquariumServices : DependencyObject
    {
        public enum Bouyancy {Floats,Sinks,Drifts}

        public static readonly DependencyProperty BouyancyProperty = DependencyProperty.RegisterAttached(
          "Bouyancy",
          typeof(Bouyancy),
          typeof(AquariumServices),
          new PropertyMetadata(Bouyancy.Floats)
        );
        public static void SetBouyancy(DependencyObject element, Bouyancy value)
        {
            element.SetValue(BouyancyProperty, value);
        }
        public static Bouyancy GetBouyancy(DependencyObject element)
        {
            return (Bouyancy)element.GetValue(BouyancyProperty);
        }
    }

Requirements

See also

DependencyProperty

Dependency properties overview

Custom dependency properties

Custom attached properties

Attached properties overview

Build date: 5/22/2012