Reference: 
https://msdn.microsoft.com/zh-tw/library/6tf1f0bc(v=vs.110).aspx

----------
List<String> Sort()

using System;
using System.Collections;

public class ReverseComparer : IComparer  
{
   // Call CaseInsensitiveComparer.Compare with the parameters reversed.
   public int Compare(Object x, Object y)  
   {
       return (new CaseInsensitiveComparer()).Compare(y, x );
   }
}

public class Example 
{
   public static void Main()  
   {
      // Create and initialize a new array. 
      String[] words = { "The", "QUICK", "BROWN", "FOX", "jumps", 
                         "over", "the", "lazy", "dog" };
      // Instantiate the reverse comparer.
      IComparer revComparer = new ReverseComparer();

      // Display the values of the array.
      Console.WriteLine( "The original order of elements in the array:" );
      DisplayValues(words);

      // Sort a section of the array using the default comparer.
      Array.Sort(words, 1, 3);
      Console.WriteLine( "After sorting elements 1-3 by using the default comparer:");
      DisplayValues(words);

      // Sort a section of the array using the reverse case-insensitive comparer.
      Array.Sort(words, 1, 3, revComparer);
      Console.WriteLine( "After sorting elements 1-3 by using the reverse case-insensitive comparer:");
      DisplayValues(words);

      // Sort the entire array using the default comparer.
      Array.Sort(words);
      Console.WriteLine( "After sorting the entire array by using the default comparer:");
      DisplayValues(words);

      // Sort the entire array by using the reverse case-insensitive comparer.
      Array.Sort(words, revComparer);
      Console.WriteLine( "After sorting the entire array using the reverse case-insensitive comparer:");
      DisplayValues(words);
   }

   public static void DisplayValues(String[] arr)  
   {
      for ( int i = arr.GetLowerBound(0); i <= arr.GetUpperBound(0);
            i++ )  {
         Console.WriteLine( "   [{0}] : {1}", i, arr[i] );
      }
      Console.WriteLine();
   }
}
// The example displays the following output:
//    The original order of elements in the array:
//       [0] : The
//       [1] : QUICK
//       [2] : BROWN
//       [3] : FOX
//       [4] : jumps
//       [5] : over
//       [6] : the
//       [7] : lazy
//       [8] : dog
//    
//    After sorting elements 1-3 by using the default comparer:
//       [0] : The
//       [1] : BROWN
//       [2] : FOX
//       [3] : QUICK
//       [4] : jumps
//       [5] : over
//       [6] : the
//       [7] : lazy
//       [8] : dog
//    
//    After sorting elements 1-3 by using the reverse case-insensitive comparer:
//       [0] : The
//       [1] : QUICK
//       [2] : FOX
//       [3] : BROWN
//       [4] : jumps
//       [5] : over
//       [6] : the
//       [7] : lazy
//       [8] : dog
//    
//    After sorting the entire array by using the default comparer:
//       [0] : BROWN
//       [1] : dog
//       [2] : FOX
//       [3] : jumps
//       [4] : lazy
//       [5] : over
//       [6] : QUICK
//       [7] : the
//       [8] : The
//    
//    After sorting the entire array using the reverse case-insensitive comparer:
//       [0] : the
//       [1] : The
//       [2] : QUICK
//       [3] : over
//       [4] : lazy
//       [5] : jumps
//       [6] : FOX
//       [7] : dog
//       [8] : BROWN