Install libgtk-sharp-beans-cil by entering the following commands in the terminal:
sudo apt update sudo apt install libgtk-sharp-beans-cil
Description:
Supplementary CLI bindings for GTK 2.14+
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 the gtk-sharp-beans assembly.
Homepage: http://github.com/mono/gtk-sharp-beans
Version: 2.14.1-4
Section: universe/cli-mono