Drag and drop to explorer causing invalid FORMATETC error (DV_E_FORMATETC)

Question

I am trying to use this great example to implement deleting virtual files in Windows Explorer. However, I was mistaken in this error. At the bottom, inside void System.Runtime.InteropServices.ComTypes.IDataObject.GetData(ref System.Runtime.InteropServices.ComTypes.FORMATETC formatetc, out System.Runtime.InteropServices.ComTypes.STGMEDIUM medium) on the first call ((System.Runtime.InteropServices.ComTypes.IDataObject)this).GetDataHere(ref formatetc, ref medium); I am returning a DV_E_FORMATETC error. As far as I can tell, all the elements of the FORMATETC structure that are passed are valid: cfFormat is "Shell IDList Array" (-16141), ptd is 0, dwAspect is DVASPECT_CONTENT, lindex is -1, and tymed is TYMED_HGLOBAL. I was kind of confused, as if in any case there was a problem, since it was created by the conductor.

I know very little about COM interoperability, so any help would be greatly appreciated.

Answer 1

After overriding about half of IDataObject, it turns out that the error code is caused by the fact that it does not support the "Shell IDList Array" in GetDataPresent ().