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DependencyObject Class

Represents an object that participates in the dependency property system.

Namespace:  System.Windows
Assembly:  WindowsBase (in WindowsBase.dll)
XMLNS for XAML: http://schemas.microsoft.com/winfx/2006/xaml/presentation, http://schemas.microsoft.com/netfx/2007/xaml/presentation

[<NameScopePropertyAttribute("NameScope", typeof(NameScope))>]
type DependencyObject =  
    class 
        inherit DispatcherObject 
    end
<DependencyObject .../>

The DependencyObject type exposes the following members.

  NameDescription
Public methodDependencyObjectInitializes a new instance of the DependencyObject class.
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  NameDescription
Public propertyDependencyObjectTypeGets the DependencyObjectType that wraps the CLR type of this instance. 
Public propertyDispatcherGets the Dispatcher this DispatcherObject is associated with. (Inherited from DispatcherObject.)
Public propertyIsSealedGets a value that indicates whether this instance is currently sealed (read-only).
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  NameDescription
Public methodCheckAccessDetermines whether the calling thread has access to this DispatcherObject. (Inherited from DispatcherObject.)
Public methodClearValue(DependencyProperty)Clears the local value of a property. The property to be cleared is specified by a DependencyProperty identifier.
Public methodClearValue(DependencyPropertyKey)Clears the local value of a read-only property. The property to be cleared is specified by a DependencyPropertyKey.
Public methodCoerceValueCoerces the value of the specified dependency property. This is accomplished by invoking any CoerceValueCallback function specified in property metadata for the dependency property as it exists on the calling DependencyObject.
Public methodEqualsDetermines whether a provided DependencyObject is equivalent to the current DependencyObject. (Overrides Object.Equals(Object).)
Protected methodFinalizeAllows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.)
Public methodGetHashCodeGets a hash code for this DependencyObject. (Overrides Object.GetHashCode().)
Public methodGetLocalValueEnumeratorCreates a specialized enumerator for determining which dependency properties have locally set values on this DependencyObject.
Public methodGetTypeGets the Type of the current instance. (Inherited from Object.)
Public methodGetValueReturns the current effective value of a dependency property on this instance of a DependencyObject.
Public methodInvalidatePropertyRe-evaluates the effective value for the specified dependency property
Protected methodMemberwiseCloneCreates a shallow copy of the current Object. (Inherited from Object.)
Protected methodOnPropertyChangedInvoked whenever the effective value of any dependency property on this DependencyObject has been updated. The specific dependency property that changed is reported in the event data.
Public methodReadLocalValueReturns the local value of a dependency property, if it exists.
Public methodSetCurrentValueSets the value of a dependency property without changing its value source.
Public methodSetValue(DependencyProperty, Object)Sets the local value of a dependency property, specified by its dependency property identifier.
Public methodSetValue(DependencyPropertyKey, Object)Sets the local value of a read-only dependency property, specified by the DependencyPropertyKey identifier of the dependency property.
Protected methodShouldSerializePropertyReturns a value that indicates whether serialization processes should serialize the value for the provided dependency property.
Public methodToStringReturns a string that represents the current object. (Inherited from Object.)
Public methodVerifyAccessEnforces that the calling thread has access to this DispatcherObject. (Inherited from DispatcherObject.)
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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. Another key class that participates in the property system is DependencyPropertyDependencyProperty enables the registration of dependency properties into the property system, and provides identification and information about each dependency property, whereas DependencyObject as a base class enables objects to use the dependency properties.

DependencyObject services and characteristics include the following:

  • 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 field in your class.

  • Attached property hosting support. You register an attached property by calling the RegisterAttached method, and storing the method's return value as a public static read-only field in your class. (There are also additional member requirements; note that this represents a WPF specific implementation for attached properties. For details, see Attached Properties Overview.) Your attached property can then be set on any class that derives from DependencyObject.

  • Get, set, and clear utility methods for values of any dependency properties that exist on the DependencyObject.

  • Metadata, coerce value support, property changed notification, and override callbacks for dependency properties or attached properties. Also, the DependencyObject class facilitates the per-owner property metadata for a dependency property.

  • A common base class for classes derived from ContentElement, Freezable, or Visual. (UIElement, another base element class, has a class hierarchy that includes Visual.)

The following example derives from DependencyObject to create a new abstract class. The class then registers an attached property and includes support members for that attached property.

No code example is currently available or this language may not be supported.

.NET Framework

Supported in: 4.5, 4, 3.5, 3.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

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