[Vala] Gtk drag and drop

[Mark Dewey <dewemark gmail com>]

I'm trying to make it so I can drag a file from Nautilus onto my opened
program window (GTK) and have it open the file when I drop it.

I tried this:
this.connect("drag_drop", this.dropDrag);
(and other similar things)

But at runtime, I got the following error (and it didn't work):
(reader:9573): GLib-GObject-WARNING **: IA__g_object_connect: invalid
signal spec "Gdk.drag_drop"

Someone suggested trying "drag-drop" instead, but that didn't work
either. I got the "drag_drop" things from Python Gtk code, since I
couldn't find documentation on the string version from Vala. Any ideas
what I'm supposed to do? Do you have a better solution than what I'm
trying (I'm not even sure if it's the right way)?