使用 Encoding 类

using System;
using System.IO;
using System.Globalization;
using System.Text;

public class Encoding_UnicodeToCP
{
   public static void Main()
   {
      // Converts ASCII characters to bytes.
      // Displays the string‘s byte representation in the 
      // specified code page.
      // Code page 1252 represents Latin characters.
      PrintCPBytes("Hello, World!",1252);
      // Code page 932 represents Japanese characters.
      PrintCPBytes("Hello, World!",932);

      // Converts Japanese characters to bytes.
      PrintCPBytes("\u307b,\u308b,\u305a,\u3042,\u306d",1252);
      PrintCPBytes("\u307b,\u308b,\u305a,\u3042,\u306d",932);
   }

   public static void PrintCPBytes(string str, int codePage)
   {
      Encoding targetEncoding;
      byte[] encodedChars;

      // Gets the encoding for the specified code page.
      targetEncoding = Encoding.GetEncoding(codePage);

      // Gets the byte representation of the specified string.
      encodedChars = targetEncoding.GetBytes(str);

      // Prints the bytes.
      Console.WriteLine
               ("Byte representation of ‘{0}‘ in Code Page  ‘{1}‘:", str, 
                  codePage);
      for (int i = 0; i < encodedChars.Length; i++)
               Console.WriteLine("Byte {0}: {1}", i, encodedChars[i]);
   }
}

// Explicitly sets the encoding to UTF-8.
Response.ContentEncoding = Encoding.UTF8;

// Sets ContentEncoding using the name of an encoding.
Response.ContentEncoding = Encoding.GetEncoding(name);

// Sets ContentEncoding using a code page number.
Response.ContentEncoding = Encoding.GetEncoding(codepageNumber);