get file name from IShellItem in IfileOperation.GetDisplayName

Question

I hooked the CopyItems method of IFileOperation to monitor/intercept file copy in windows. My problem is how can i retrieve the full file name<

Answer 1

The CopyItems method copies potentially multiple items. So right off the bat you are mistaken looking for a single file name. This is a very complex API and you do need to read the documentation carefully and understand clearly how the function works.

The psiDestinationFolder parameter is an IShellItem that identifies the destination. Use the GetDisplayName method to get the file path.

The other parameter, punkItems is more complex. It is documented like this:

Pointer to the IUnknown of the IShellItemArray, IDataObject, or IEnumShellItems object which represents the group of items to be copied. You can also point to an IPersistIDList object to represent a single item, effectively accomplishing the same function as IFileOperation::CopyItem.

This is telling you that there could be an IShellItemArray, IDataObject, IEnumShellItems or a IPersistIDList object behind the IUnknown interface that you receive. And that there could be multiple items in that single object, each one to be copied to the destination folder. You will need to query punkItems for each possible interface in turn until you find out which of these possibilities you have to deal with. And then handle each one with special code. In order to test this you'll need to write code that calls CopyItems with each of the possible interfaces. You'll find out how to do all of this from the documentation of each of the four interfaces. If you don't already know shell programming and COM well, expect to do so by the time you complete this work.

Finally, I doubt that this is a very good way to detect file copying. Files are copied using many different APIs. And IFileOperation.CopyItems is but one of them. If you only hook IFileOperation.CopyItems then you'll miss a lot of file copy operations.