Articolo
11/18/2011

DependencyPropertyChangedEventArgs Structure

Microsoft Silverlight will reach end of support after October 2021. Learn more.

Provides data for a PropertyChangedCallback implementation.

Namespace: System.Windows
Assembly: System.Windows (in System.Windows.dll)

Syntax

'Declaration
Public Structure DependencyPropertyChangedEventArgs

public struct DependencyPropertyChangedEventArgs

The DependencyPropertyChangedEventArgs type exposes the following members.

Properties

	Name	Description
	NewValue	Gets the value of the property after the change.
	OldValue	Gets the value of the property before the change.
	Property	Gets the identifier for the dependency property where the value change occurred.

Top

Methods

	Name	Description
	Equals	Indicates whether this instance and a specified object are equal. (Inherited from ValueType.)
	Finalize	Allows an object to try to free resources and perform other cleanup operations before the Object is reclaimed by garbage collection. (Inherited from Object.)
	GetHashCode	Returns the hash code for this instance. (Inherited from ValueType.)
	GetType	Gets the Type of the current instance. (Inherited from Object.)
	MemberwiseClone	Creates a shallow copy of the current Object. (Inherited from Object.)
	ToString	Returns the fully qualified type name of this instance. (Inherited from ValueType.)

Top

Remarks

The scenario for PropertyChangedCallback is to use the arguments to report old and new values that come from the property system evaluation of the property. A callback that processes old and new values might choose special handling depending on these values. Some example scenarios include:

Choosing to not respond to value changes that are deemed insignificant.
Rejecting property changes that fail a property-specific or circumstantial validation.
Checking/setting other property values that exist in a dependency relationship with the property that changed.
Raising an event from the class.

Version Information

Silverlight

Supported in: 5, 4, 3

Silverlight for Windows Phone

Supported in: Windows Phone OS 7.1, Windows Phone OS 7.0

Platforms

For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.

Thread Safety

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

Condividi tramite