[Nix-dev] Trying to compile and run mono gtk example but problem install gtksharp2

[Paul Dufresne]

I am trying to compile the GTK example on:
http://www.mono-project.com/docs/getting-started/mono-basics/

Soon I discovered that I need to have gtk-sharp v.2 in my environment.

Searching gtk-sharp on https://nixos.org/nixos/packages.html
I concluded that I should have:

In my configuration.nix I have:
   environment.systemPackages = with pkgs; [
     gtksharp2
     wget
     firefoxWrapper
     ...

on nixos-rebuild switch I get undefined variable "gtksharp2".

I found that
   environment.systemPackages = with pkgs; [
     gtk-sharp
     wget
     firefoxWrapper
do seems to work, but when
[nix-shell:~/mycs]$ mono helloGtk.exe

Unhandled Exception:
System.IO.FileNotFoundException: Could not load file or assembly
'gtk-sharp, Version=2.12.0.0, Culture=neutral,
PublicKeyToken=35e10195dab3c99f' or one of its dependencies.
File name: 'gtk-sharp, Version=2.12.0.0, Culture=neutral,
PublicKeyToken=35e10195dab3c99f'
[ERROR] FATAL UNHANDLED EXCEPTION: System.IO.FileNotFoundException:
Could not load file or assembly 'gtk-sharp, Version=2.12.0.0,
Culture=neutral, PublicKeyToken=35e10195dab3c99f' or one of its
dependencies.
File name: 'gtk-sharp, Version=2.12.0.0, Culture=neutral,
PublicKeyToken=35e10195dab3c99f'

[nix-shell:~/mycs]$

So I guess it is gtksharp v.1... not sure.

I am using:
[root at nixos:/home/paul/mycs]# nix-channel --list
nixos https://nixos.org/channels/nixos-unstable

and [root at nixos:/home/paul/mycs]# ls
/etc/nixos/nixpkgs/pkgs/development/libraries/gtk-sharp-2/
builder.sh  default.nix

[root at nixos:/home/paul/mycs]#

I did try to add gtk-sharp-2 in    environment.systemPackages = with pkgs; [

but that too did not worked.