C# function to drag/drop email

We have Lotus Notes 8.5 I can see you can drag an email from inbox to the desktop and it creates an .eml file which is great. Now what I want to do is have a system tray icon app written in C#. You drag the LN email over the sytem tray icon and it just writes the eml file to say root of c:. Its the drag and drop bit I am struggling with and getting it to write the drag drop email as an eml file if drag dropped over an C# icon application. Tried looking for DataFormats.FileDrop but not seem to be valid. Therefore after the C# code to do this.

e.g. See attachment which works for files in windows I just want same thing with a Lotus note dragged onto the form