DataTable 行转列

using System;
using System.Collections.Generic;
using System.Data;
using System.Linq;
using System.Text;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            DataTable dt = new DataTable();
            dt.Columns.Add("id");
            dt.Columns.Add("code");
            dt.Columns.Add("amount");
            dt.Rows.Add("m1", "cash", "90");
            dt.Rows.Add("m1", "nets", "50");
            dt.Rows.Add("m2", "cash", "190");
            dt.Rows.Add("m2", "nets", "150");
            dt.Rows.Add("m2", "another", "222");
            dt.Rows.Add("m3", "cash", "150");
            dt.Rows.Add("m3", "another", "100");
            Console.WriteLine("Source:");
            DisplayTable(dt);
            Console.WriteLine("Target:");
            DisplayTable(ConvertDataTable(dt));

        }

        static DataTable ConvertDataTable(DataTable source)
        {
            DataTable dt = new DataTable();
            dt.Columns.Add("id");
            var columns = (from x in source.Rows.Cast() select x[1].ToString()).Distinct();
            foreach (var item in columns) dt.Columns.Add(item);
            var data = from x in source.Rows.Cast()
                       group x by x[0] into g
                       select new { Key = g.Key.ToString(), Items = g };
            data.ToList().ForEach(x => 
                {
                    string[] array = new string[dt.Columns.Count];
                    array[0] = x.Key;
                    for (int i = 1; i < dt.Columns.Count; i++)
                        array[i] = (from y in x.Items
                                    where y[1].ToString() == dt.Columns[i].ToString()
                                    select y[2].ToString())
                                   .SingleOrDefault();
                    dt.Rows.Add(array);
                });
            return dt;
        }

        static void DisplayTable(DataTable dt)
        { 
            dt.Columns.Cast().ToList().ForEach(x => Console.Write(x + "\t"));
            Console.WriteLine();
            dt.Rows.Cast().ToList().ForEach(x =>
                {
                    x.ItemArray.ToList().ForEach(y => Console.Write(y.ToString() + "\t"));
                    Console.WriteLine();
                });
        }
    }
}

Source:
id      code    amount
m1      cash    90
m1      nets    50
m2      cash    190
m2      nets    150
m2      another 222
m3      cash    150
m3      another 100
Target:
id      cash    nets    another
m1      90      50
m2      190     150     222
m3      150             100
Press any key to continue . . .