Encoding.GetBytes Method (array<Char[], Int32, Int32)

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When overridden in a derived class, encodes a set of characters from the specified character array into a sequence of bytes.

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

Syntax

'Declaration
Public Overridable Function GetBytes ( _
    chars As Char(), _
    index As Integer, _
    count As Integer _
) As Byte()

public virtual byte[] GetBytes(
    char[] chars,
    int index,
    int count
)

Parameters

• chars
  Type: array<System.Char[]
  The character array containing the set of characters to encode.

• index
  Type: System.Int32
  The zero-based index of the first character to encode.

• count
  Type: System.Int32
  The number of characters to encode.

Return Value

Type: array<System.Byte[]
A byte array containing the results of encoding the specified set of characters.

Exceptions

Exception	Condition
ArgumentNullException	chars is nulla null reference (Nothing in Visual Basic).
ArgumentOutOfRangeException	index or count is less than zero. -or- index and count do not denote a valid range in chars.
EncoderFallbackException	A fallback occurred (see Understanding Encodings for complete explanation).

Remarks

If the data to be converted is available only in sequential blocks (such as data read from a stream) or if the amount of data is so large that it needs to be divided into smaller blocks, the application should use the Decoder or the Encoder provided by the GetDecoder method or the GetEncoder method, respectively, of a derived class.

For a discussion of programming considerations for use of this method, see the Encoding class description.

Examples

The following code example determines the number of bytes required to encode three characters from 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 three characters starting at index 4, and print out the counts and the resulting bytes.
      PrintCountsAndBytes(myChars, 4, 3, u8)
      PrintCountsAndBytes(myChars, 4, 3, u16LE)
      PrintCountsAndBytes(myChars, 4, 3, u16BE)
   End Sub 

   Public Shared Sub PrintCountsAndBytes(ByVal chars() As Char, ByVal index As Integer, _ 
                                         ByVal count As Integer, 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, index, count)
      outputBlock.Text += String.Format(" {0,-3}", iBC)

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

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

      ' The following is an alternative way to encode the array of chars:
      '       The following line creates the array with the exact number of elements required.
      ' Dim bytes(iBC - 1) As Byte
      ' enc.GetBytes( chars, index, count, bytes, bytes.GetLowerBound(0) )

      ' 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       : 6   12  :CE B2 F1 8F B3 BF
'       System.Text.UnicodeEncoding    : 6   8   :B2 03 FF D8 FF DC
'       System.Text.UnicodeEncoding    : 6   8   :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 three characters starting at index 4, and print out the counts and the resulting bytes.
      PrintCountsAndBytes(myChars, 4, 3, u8);
      PrintCountsAndBytes(myChars, 4, 3, u16LE);
      PrintCountsAndBytes(myChars, 4, 3, u16BE);
   }

   public static void PrintCountsAndBytes(char[] chars, int index, int count, 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, index, count);
      outputBlock.Text += String.Format(" {0,-3}", iBC);

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

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

      // The following is an alternative way to encode the array of chars:
      // byte[] bytes = new byte[iBC];
      // enc.GetBytes( chars, index, count, bytes, bytes.GetLowerBound(0) );

      // 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 example produces the following output.
   System.Text.UTF8Encoding       : 6   12  :CE B2 F1 8F B3 BF
   System.Text.UnicodeEncoding    : 6   8   :B2 03 FF D8 FF DC
   System.Text.UnicodeEncoding    : 6   8   :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.

See Also

Reference

Encoding Class

GetBytes Overload

System.Text Namespace

GetEncoder

GetByteCount

GetMaxByteCount