using System;
using System.Globalization;
using System.Linq;
using System.Collections;
using System.Collections.Generic;

public class Test
{
		class grpitem
	    {
	        public string groupCode;
	        public string item;
	    }
        
        static List<grpitem> list = new List<grpitem>()
        {
             new grpitem() {groupCode="3", item="b"},
             new grpitem() {groupCode="1", item="b"},
             new grpitem() {groupCode="3", item="c"},
             new grpitem() {groupCode="2", item="b"},
             new grpitem() {groupCode="2", item="a"},
             new grpitem() {groupCode="2", item="c"},
             new grpitem() {groupCode="1", item="a"},
             new grpitem() {groupCode="3", item="a"},
             new grpitem() {groupCode="3", item="d"}
        };
        public static void Main()
        {
            IEnumerable<grpitem> ordered = list.GroupBy(grp => grp.groupCode)
                .SelectMany(g => g.OrderBy(grp => grp.item));
	
	        foreach(grpitem g in ordered)
	            Console.WriteLine("groupCode:{0} item:{1}",g.groupCode,g.item);
     
}
}