UnicodeEncoding Constructor (Boolean, Boolean, Boolean)


Initializes a new instance of the UnicodeEncoding class. Parameters specify whether to use the big endian byte order, whether to provide a Unicode byte order mark, and whether to throw an exception when an invalid encoding is detected.

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

public UnicodeEncoding(
	bool bigEndian,
	bool byteOrderMark,
	bool throwOnInvalidBytes


Type: System.Boolean

true to use the big endian byte order (most significant byte first); false to use the little endian byte order (least significant byte first).

Type: System.Boolean

true to specify that the GetPreamble method returns a Unicode byte order mark; otherwise, false. See the Remarks section for more information.

Type: System.Boolean

true to specify that an exception should be thrown when an invalid encoding is detected; otherwise, false.

The byteOrderMark parameter controls the operation of the GetPreamble method. If true, the method returns a byte array containing the Unicode byte order mark (BOM) in UTF-16 format. If false, it returns a zero-length byte array. However, setting byteOrderMark to true does not cause the GetBytes method to prefix the BOM at the beginning of the byte array, nor does it cause the GetByteCount method to include the number of bytes in the BOM in the byte count.

If the throwOnInvalidBytes parameter is true, a method that detects an invalid byte sequence throws System.ArgumentException. Otherwise, the method does not throw an exception, and the invalid sequence is ignored.


For security reasons, your applications are recommended to use this constructor to create an instance of the UnicodeEncoding class and turn on error detection by setting throwOnInvalidBytes to true.

The following example demonstrates the behavior of UnicodeEncoding, both with error detection enabled and without.

using System;
using System.Text;

public class SamplesUnicodeEncoding  {

   public static void Main()  {

      // Create an instance of UnicodeEncoding using little-endian byte order.
      // This will be used for encoding.
      UnicodeEncoding u16LE     = new UnicodeEncoding( false, true );

      // Create two instances of UnicodeEncoding using big-endian byte order: one with error detection and one without.
      // These will be used for decoding.
      UnicodeEncoding u16withED = new UnicodeEncoding( true, true, true );
      UnicodeEncoding u16noED   = new UnicodeEncoding( true, true, false );

      // Create byte arrays from the same string containing the following characters:
      //    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)
      //    Latin Capital Letter U with  Diaeresis (U+00DC)
      String myStr = "za\u0306\u01FD\u03B2\u00DC";

      // Encode the string using little-endian byte order.
      byte[] myBytes = new byte[u16LE.GetByteCount( myStr )];
      u16LE.GetBytes( myStr, 0, myStr.Length, myBytes, 0 );

      // Decode the byte array with error detection.
      Console.WriteLine( "Decoding with error detection:" );
      PrintDecodedString( myBytes, u16withED );

      // Decode the byte array without error detection.
      Console.WriteLine( "Decoding without error detection:" );
      PrintDecodedString( myBytes, u16noED );


   // Decode the bytes and display the string.
   public static void PrintDecodedString( byte[] bytes, Encoding enc )  {

      try  {
         Console.WriteLine( "   Decoded string: {0}", enc.GetString( bytes, 0, bytes.Length ) );
      catch ( System.ArgumentException e )  {
         Console.WriteLine( e.ToString() );




Universal Windows Platform
Available since 8
.NET Framework
Available since 2.0
Portable Class Library
Supported in: portable .NET platforms
Available since 2.0
Windows Phone Silverlight
Available since 7.0
Windows Phone
Available since 8.1
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