How do I distinguish a file or a folder in a drag and drop event in c#?

I have a form that you drag and drop files into and I was wondering how can I make the application know if the data is a file or a folder.

My first attempt was to look for a "." in the data but then some folders do have a . in them. I've also tried doing a File.Exists and a Directory.Exists condition but then it only searches on the current application path and not anywhere else.

Is there anyway I can somehow apply the .Exists in a specific directory or is there a way I can check what type of data is dragged into the form?