Search code examples
delphicastingdelphi-6

Convert OleVariant to Object in Delphi

I'm working on this project where we don't have the source code for large chunks of the project, but we have the .DLL files with some information. There is a bug in the DLL files. I am able to create a subclass of the class with the bug in it and I would like to downcast the object which already exists at a point I have access to it. The issue is that at any point I have access to the object, it's cast as a Variant. I've tried the following (edited to remove context):

tempSubclass := Subclass(ParentClass(Integer(oleVariantCast)));

but I get the following error:

Could not convert variant of type (Dispatch) into type (Integer)

Is there any other way to get the pointer to the object out of the OleVariant and/or do the typecasting involved?

Thank you.

EDIT: Yes, the Parentclass implements IDispatch. CORRECTION: The parentclass implements an interface which inherits from IDispatch.

Solution

  • Try type cast to IUnknown first.

    tempSubclass := Subclass(ParentClass(Integer(IUnknown(oleVariantCast))));