Install gtk-sharp2 by entering the following commands in the terminal:
sudo apt update sudo apt install gtk-sharp2
Description:
GTK# 2.10 suite, CLI bindings for GTK+
GTK# 2.10 is a CLI (.NET) language binding for the GTK+ 2.10 toolkit . gtk-sharp2 is a metapackage containing dependencies for the GTK# 2.10 suite.
Homepage: http://www.mono-project.com/GtkSharp
Version: 2.12.40-2
Section: universe/libs