Invoked 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.
Assembly: WindowsBase (in WindowsBase.dll)
This method is not intended to generally detect individual property changes or perform invalidations of properties on a per-case basis. is instead intended for modifications of the general invalidation pattern, if certain information is known about wide classifications of properties. For example, changes in a Freezable might be changes in the value types of the Freezable, or might be subproperties, where the changes are within other Freezable references. The Freezable override implementation of uses internal information to determine whether the properties are subproperties, and provides appropriate base class logic for either case.
is potentially invoked many times during the life of an object. Therefore, you can achieve better performance for the overall property system if you override the metadata of specific properties and then attach CoerceValueCallback or PropertyChangedCallback functions for individual properties. However, you would use this method if a DependencyObject includes a significant number of value-interrelated dependency properties, or if it includes logic such as rendering behavior that must be rerun for several related cases of property invalidations.Notes to Inheritors
Always call the base implementation. Failure to do this will significantly disable the entire WPF property system, causing incorrect values to be reported.
The method has high potential for introducing reentrancy issues through your implementation. Avoid the following possible reentrancy cases when implementing:
Do not introduce modal UI or otherwise hold up the UI thread.
Do not enter any message pump from within . Message responses (in particular, native handling that you might not be aware of) might trigger further property changes.
Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2