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Encoding.BigEndianUnicode Property

Updated: October 2010

Gets an encoding for the UTF-16 format that uses the big-endian byte order.

Namespace:  System.Text
Assembly:  mscorlib (in mscorlib.dll)

public static Encoding BigEndianUnicode { get; }

Property Value

Type: System.Text.Encoding
An encoding for the UTF-16 format that uses the big-endian byte order.

The UnicodeEncoding object that is returned by this property may not have the appropriate behavior for your application. It uses replacement fallback to replace each string that it cannot encode and each byte that it cannot decode with a question mark ("?") character. Instead, you can call the UnicodeEncoding.UnicodeEncoding(Boolean, Boolean, Boolean) constructor to instantiate a big endian UnicodeEncoding object whose fallback is either an EncoderFallbackException or a DecoderFallbackException, as the following example illustrates.


using System;
using System.Text;

public class Example
{
   public static void Demo(System.Windows.Controls.TextBlock outputBlock)
   {
      byte[] bytes = { 0x00, 0x20, 0xd8, 0x01, 0x00, 0x68, 0xA7, 0x00 };
      Encoding enc = new UnicodeEncoding(true, true, true);

      try
      {
         string value = enc.GetString(bytes, 0, bytes.Length);
         outputBlock.Text += "\n";
         outputBlock.Text += String.Format("'{0}'", value) + "\n";
      }
      catch (DecoderFallbackException e)
      {
         outputBlock.Text += String.Format("Unable to decode {0} at index {1}",
                           ShowBytes(e.BytesUnknown), e.Index) + "\n";
      }
   }

   private static string ShowBytes(byte[] bytes)
   {
      string returnString = null;
      foreach (var byteValue in bytes)
         returnString += String.Format("0x{0:X2} ", byteValue);

      return returnString.Trim();
   }
}
// The example displays the following output:
//        Unable to decode 0xD8 0x01 at index 4


The returned UnicodeEncoding object has BodyName, HeaderName, and WebName properties, which yield the name "unicodeFFFE". Although the UTF-16 big endian byte order mark is hexadecimal FEFF, the name "unicodeFFFE" was chosen because the byte order mark appears as hexadecimal FFFE on little endian Windows computers.

The following example defines an array of Unicode-encoded bytes, decodes them using the GetString method, converts them to a big-endian Unicode-encoded byte array, and again decodes them using the GetString method.


using System;
using System.Text;

public class Example
{
   public static void Demo(System.Windows.Controls.TextBlock outputBlock)
   {
      // Define a byte array equivalent to the string "Hello!"
      byte[] helloBytes = {0x48, 0, 0x65, 0, 0x6C, 0, 0x6C, 0, 0x6F, 0, 0x21, 0};
      outputBlock.Text += "Original bytes: ";
      foreach (byte helloByte in helloBytes)
         outputBlock.Text += helloByte.ToString("X2") + " ";

      outputBlock.Text += "\n";

      // Create a unicode string.
      Encoding unicodeEnc = Encoding.Unicode;
      string unicodeString = unicodeEnc.GetString(helloBytes, 0, helloBytes.Length);
      outputBlock.Text += String.Format("Bytes encoded using Unicode encoding: {0}\n",
                                        unicodeString);

      // Convert to big endian Unicode.
      byte[] newHelloBytes = Encoding.Convert(Encoding.Unicode, Encoding.BigEndianUnicode, helloBytes);      
      outputBlock.Text += "Big Endian bytes: ";
      foreach (byte newHelloByte in newHelloBytes)
         outputBlock.Text += newHelloByte.ToString("X2") + " ";

      // Convert big endian Unicode-encoded bytes to a string.
      outputBlock.Text += "\n";
      outputBlock.Text += "Resulting string: " + Encoding.BigEndianUnicode.GetString(newHelloBytes, 0, newHelloBytes.Length);
   }
}
// The example displays the following output:
//       Original bytes: 48 00 65 00 6C 00 6C 00 6F 00 21 00
//       Bytes encoded using Unicode encoding: Hello!
//       Big Endian bytes: 00 48 00 65 00 6C 00 6C 00 6F 00 21
//       Resulting string: Hello!


The following example determines the number of bytes required to encode a character array, encodes the characters, and displays the resulting bytes.


using System;
using System.Text;

public class Example
{
   private static System.Windows.Controls.TextBlock outputBlock;

   public static void Demo(System.Windows.Controls.TextBlock outBlock)
   {
      outputBlock = outBlock;

      // The characters to encode:
      //    Latin Small Letter Z (U+007A)
      //    Latin Small Letter A (U+0061)
      //    Combining Breve (U+0306)
      //    Latin Small Letter AE With Acute (U+01FD)
      //    Greek Small Letter Beta (U+03B2)
      //    a high-surrogate value (U+D8FF)
      //    a low-surrogate value (U+DCFF)
      char[] myChars = new char[] { 'z', 'a', '\u0306', '\u01FD', '\u03B2', '\uD8FF', '\uDCFF' };

      // Get different encodings.
      Encoding u8 = Encoding.UTF8;
      Encoding u16LE = Encoding.Unicode;
      Encoding u16BE = Encoding.BigEndianUnicode;

      // Encode the entire array, and print out the counts and the resulting bytes.
      PrintCountsAndBytes(myChars, u8);
      PrintCountsAndBytes(myChars, u16LE);
      PrintCountsAndBytes(myChars, u16BE);
   }

   public static void PrintCountsAndBytes(char[] chars, Encoding enc)
   {
      // Display the name of the encoding used.
      outputBlock.Text += String.Format("{0,-30} :", enc.ToString());

      // Display the exact byte count.
      int iBC = enc.GetByteCount(chars);
      outputBlock.Text += String.Format(" {0,-3}", iBC);

      // Display the maximum byte count.
      int iMBC = enc.GetMaxByteCount(chars.Length);
      outputBlock.Text += String.Format(" {0,-3} :", iMBC);

      // Encode the array of chars.
      byte[] bytes = enc.GetBytes(chars);

      // Display all the encoded bytes.
      PrintHexBytes(bytes);
   }

   public static void PrintHexBytes(byte[] bytes)
   {
      if ((bytes == null) || (bytes.Length == 0))
         outputBlock.Text += "<none>" + "\n";
      else
      {
         for (int i = 0; i < bytes.Length; i++)
            outputBlock.Text += String.Format("{0:X2} ", bytes[i]);
         outputBlock.Text += "\n";
      }
   }
}
/* 
This code produces the following output.
   System.Text.UTF8Encoding       : 12  24  :7A 61 CC 86 C7 BD CE B2 F1 8F B3 BF
   System.Text.UnicodeEncoding    : 14  16  :7A 00 61 00 06 03 FD 01 B2 03 FF D8 FF DC
   System.Text.UnicodeEncoding    : 14  16  :00 7A 00 61 03 06 01 FD 03 B2 D8 FF DC FF
*/


Silverlight

Supported in: 5, 4, 3

Silverlight for Windows Phone

Supported in: Windows Phone OS 7.1, Windows Phone OS 7.0

XNA Framework

Supported in: Xbox 360, Windows Phone OS 7.0

For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.

Date

History

Reason

October 2010

Noted replacement fallback behavior.

Customer feedback.

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