Provides data for various property changed events. Typically these events report effective value changes in the value of a read-only dependency property. Another usage is as part of a PropertyChangedCallback implementation.
Assembly: WindowsBase (in WindowsBase.dll)
|DependencyPropertyChangedEventArgs(DependencyProperty, Object, Object)|
Initializes a new instance of theclass.
Determines whether the providedis equivalent to the current .
Determines whether the provided object is equivalent to the current ValueType.Equals(Object).).(Overrides
Gets a hash code for this ValueType.GetHashCode().). (Overrides
Returns the fully qualified type name of this instance.(Inherited from ValueType.)
Determines whether two specifiedobjects have the same value.
Determines whether two specifiedobjects are different.
The events that use the DependencyPropertyChangedEventHandler method implementations for handlers, generally follow the naming pattern Is*Changed, and are generally implemented as common language runtime (CLR) events without RoutedEvent backing (they are not routed events). Some class handling methods that "handle" otherwise unexposed events that report a state change through a property change, such as ButtonBase.OnIsPressedChanged, also use the class for event data.class for event data, and the
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, such as choosing to not respond to value changes that are deemed insignificant.
The following example uses the PropertyChangedCallback for a particular property of a custom class that also defines events. The callback takes the results of old and new values from the property system as communicated by , and repackages these into a different events arguments class RoutedPropertyChangedEventArgs<T>. The new arguments are then used as the data for a "ValueChanged" event defined by and raised by the custom class.class in the context of a
Available since 3.0
Available since 2.0
Windows Phone Silverlight
Available since 7.0
Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.