The way I read the original post there are 2 questions:
 How do I associate an application with a file type?
There used to be a way to do this in Gnome2 but our Gnome Overlords took it away so what I do is install something they can't touch - the XFCE file manager Thunar:
- Code: Select all
sudo apt-get install thunar
Then open Thunar > right click any *.txt file > Open with other application > and you will see this pop-up:Once you make the association in Thunar it will apply to everything else.
As a side benefit you will also get another Gnome2 option that has vanished in Gnome3 and that's "Use a Cusom Command" which may be the way you answer question 2 of your post.
 How do I associate a Wine application with a file type.
That I do not know as I do not use Wine, sorry.