Install libgtk-sharp-beans2.0-cil-dev by entering the following commands in the terminal:
sudo apt update sudo apt install libgtk-sharp-beans2.0-cil-dev
Description:
Supplementary CLI bindings for GTK 2.14+ - development package
This package provides the gtk-sharp-beans assembly that allows CLI (.NET) programs to use GTK+ methods from GTK+ 2.14 and above, which are not exposed by GTK#. . This package contains development files for the gtk-sharp-beans library, and should be used for compilation.
Homepage: http://github.com/mono/gtk-sharp-beans
Version: 2.14.1-4
Section: universe/cli-mono