Enables a merge of the source metadata with base metadata.
Assembly: PresentationFramework (in PresentationFramework.dll)
This method is used internally when metadata is being overridden.Notes to Inheritors
Classes that derive from PropertyMetadata (or this class particularly) should override this method to account for any metadata properties they have added in their implementations. For instance, your implementation might have added a new flagwise enumeration value, and the implementation should then be able to combine those flags correctly.
Always call the base implementation prior to your own implementation, because the base implementation takes care of merging all the properties already defined on previous types in the hierarchy.
The behavior also implements the behavior when you override the property metadata on an existing dependency property by calling OverrideMetadata., using override metadata that is FrameworkPropertyMetadata.