Partager via


Encoding.BigEndianUnicode Property

Microsoft Silverlight will reach end of support after October 2021. Learn more.

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)

Syntax

'Declaration
Public Shared ReadOnly Property BigEndianUnicode As Encoding
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.

Remarks

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.

Imports System.Text

Module Example
   Public Sub Demo(ByVal outputBlock As System.Windows.Controls.TextBlock)
      Dim bytes() As Byte = {&H0, &H20, &HD8, &H1, &H0, &H68, &HA7, &H0}
      Dim enc As Encoding = New UnicodeEncoding(True, True, True)

      Try
         Dim value As String = enc.GetString(bytes, 0, bytes.Length)
         outputBlock.Text &= vbCrLf
         outputBlock.Text += String.Format("'{0}'", value) & vbCrLf
      Catch e As DecoderFallbackException
         outputBlock.Text += String.Format("Unable to decode {0} at index {1}",  
                           ShowBytes(e.BytesUnknown), e.Index) & vbCrLf
      End Try
   End Sub

   Private Function ShowBytes(ByVal bytes As Byte()) As String
      Dim returnString As String = Nothing
      For Each byteValue In bytes
         returnString += String.Format("0x{0:X2} ", byteValue)
      Next
      Return returnString.Trim()
   End Function
End Module
' The example displays the following output:
'       Unable to decode 0xD8 0x01 at index 4
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.

Examples

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.

Imports System.Text

Public Class Example
   Public Shared Sub Demo(ByVal outputBlock As System.Windows.Controls.TextBlock)
      ' Define a byte array equivalent to the string "Hello!"
      Dim helloBytes() As Byte = {&h48, 0, &h65, 0, &h6C, 0, &h6C, 0, &h6F, 0, &h21, 0}
      outputBlock.Text += "Original bytes: "
      For Each helloByte As Byte In helloBytes
         outputBlock.Text += helloByte.ToString("X2") + " "
      Next
      outputBlock.Text += vbCrLf

      ' Create a unicode string.
      Dim unicodeEnc As Encoding = Encoding.Unicode
      Dim unicodeString As String = unicodeEnc.GetString(helloBytes, 0, helloBytes.Length)
      outputBlock.Text += "Bytes encoded using Unicode encoding: " + unicodeString + vbCrLf

      ' Convert to big endian Unicode.
      Dim newHelloBytes() As Byte = Encoding.Convert(Encoding.Unicode, Encoding.BigEndianUnicode, helloBytes)      
      outputBlock.Text += "Big Endian bytes: "
      For Each newHelloByte As Byte In newHelloBytes
         outputBlock.Text += newHelloByte.ToString("X2") + " "
      Next

      ' Convert big endian Unicode-encoded bytes to a string.
      outputBlock.Text += vbCrLf
      outputBlock.Text += "Resulting string: " + Encoding.BigEndianUnicode.GetString(newHelloBytes, 0, newHelloBytes.Length)
   End Sub
End Class
' 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!
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.

Imports System.Text

Public Class Example

   Private Shared outputBlock As System.Windows.Controls.TextBlock

   Public Shared Sub Demo(ByVal outBlock As System.Windows.Controls.TextBlock)

      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)
      Dim myChars() As Char = {"z"c, "a"c, ChrW(&H306), ChrW(&H1FD), ChrW(&H3B2), ChrW(&HD8FF), ChrW(&HDCFF)}

      ' Get different encodings.
      Dim u8 As Encoding = Encoding.UTF8
      Dim u16LE As Encoding = Encoding.Unicode
      Dim u16BE As Encoding = Encoding.BigEndianUnicode

      ' Encode the entire array, and print out the counts and the resulting bytes.
      PrintCountsAndBytes(myChars, u8)
      PrintCountsAndBytes(myChars, u16LE)
      PrintCountsAndBytes(myChars, u16BE)
   End Sub 

   Public Shared Sub PrintCountsAndBytes(ByVal chars() As Char, ByVal enc As Encoding)
      ' Display the name of the encoding used.
      outputBlock.Text += String.Format("{0,-30} :", enc.ToString())

      ' Display the exact byte count.
      Dim iBC As Integer = enc.GetByteCount(chars)
      outputBlock.Text += String.Format(" {0,-3}", iBC)

      ' Display the maximum byte count.
      Dim iMBC As Integer = enc.GetMaxByteCount(chars.Length)
      outputBlock.Text += String.Format(" {0,-3} :", iMBC)

      ' Encode the array of chars.
      Dim bytes As Byte() = enc.GetBytes(chars)

      ' Display all the encoded bytes.
      PrintHexBytes(bytes)
   End Sub 

   Public Shared Sub PrintHexBytes(ByVal bytes() As Byte)
      If bytes Is Nothing OrElse bytes.Length = 0 Then
         outputBlock.Text &= "<none>" & vbCrLf
      Else
         Dim i As Integer
         For i = 0 To bytes.Length - 1
            outputBlock.Text += String.Format("{0:X2} ", bytes(i))
         Next i
         outputBlock.Text &= vbCrLf
      End If
   End Sub 
End Class 
' This example 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
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
*/

Version Information

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

Platforms

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

Change History

Date

History

Reason

October 2010

Noted replacement fallback behavior.

Customer feedback.