Introduction

A adobe photoshop like color picker dialog.

string	ColorHexa	gets/sets the current color in hexa
GraphUtil.CMYK	ColorCMYK	gets/sets the current cmyk color
Gdk.Color	ColorGDK	gets/sets the current gdk color
System.Drawing.Color	ColorRGB	gets/sets the current rgb color
GraphUtil.HSL	ColorHSL	gets/sets the current hsl color

Details

you can use the HColorPicker dialog or the HColorPickerWidget widget.

using System.Drawing;
...
	HColorPickerDialog dlg = new HColorPickerDialog();
	dlg.ColorRGB   = Color.AliceBlue;
	if( dlg.Run() == (int)Gtk.ResponseType.Ok )
	{
		Console.WriteLine( dlg.ColorHexa );
	}
	dlg.Destroy()