Override GetInstance to return the object that represents the data from a Variant of the custom Type. TPublishableVariantType implements all the published properties of that object so that they are published properties of the Variant. 

V is the data from a Variant of the custom type. This data must include a reference to an object that represents the Variant's data, and which GetInstance returns. 

GetInstance is abstract or, in C++ terminology, pure virtual in TPublishableVariantType, which means it has no implementation. Descendant classes override this method to enable Variants to publish the properties from the object that implements their data. 

GetProperty 

SetProperty 

Supporting Properties and Methods in Custom Variants