GTK#
Introduction
GTK (GIMP Toolkit) is a library for creating graphical user
interfaces. It is licensed using the LGPL license, so you can
develop open software, free software, or even commercial non-free
software using GTK without having to spend anything for licenses or
royalties.
It's called the GIMP toolkit because it was originally written for
developing the GNU Image Manipulation Program (GIMP), but GTK has
now been used in a large number of software projects, including the
GNU Network Object Model Environment (GNOME) project. GTK is built
on top of GDK (GIMP Drawing Kit) which is basically a wrapper
around the low-level functions for accessing the underlying
windowing functions (Xlib in the case of the X windows system), and
gdk-pixbuf, a library for client-side image manipulation.
Gtk# is a binding for mono to this great toolkit, that is usable
from any Mono language including MonoBasic and C#.