Encoding.GetByteCount Method (Char[], Int32, Int32)

When overridden in a derived class, calculates the number of bytes produced by encoding a set of characters from the specified character array.

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

public:
virtual int GetByteCount (
	array<wchar_t>^ chars, 
	int index, 
	int count
) abstract
public abstract int GetByteCount (
	char[] chars, 
	int index, 
	int count
)
public abstract function GetByteCount (
	chars : char[], 
	index : int, 
	count : int
) : int

Parameters

chars

The character array containing the set of characters to encode.

index

The index of the first character to encode.

count

The number of characters to encode.

Return Value

The number of bytes produced by encoding the specified characters.

Exception typeCondition

ArgumentNullException

chars is a 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.

To calculate the exact array size required by GetBytes to store the resulting bytes, use GetByteCount. To calculate the maximum array size, use GetMaxByteCount. The GetByteCount method generally allows you to allocate less memory, whereas the GetMaxByteCount method generally executes faster.

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.

using namespace System;
using namespace System::Text;
void PrintCountsAndBytes( array<Char>^chars, int index, int count, Encoding^ enc );
void PrintHexBytes( array<Byte>^bytes );
int main()
{
   
   // 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)
   array<Char>^myChars = gcnew array<Char>{
      L'z',L'a',L'\u0306',L'\u01FD',L'\u03B2',L'\xD8FF',L'\xDCFF'
   };
   
   // Get different encodings.
   Encoding^ u7 = Encoding::UTF7;
   Encoding^ u8 = Encoding::UTF8;
   Encoding^ u16LE = Encoding::Unicode;
   Encoding^ u16BE = Encoding::BigEndianUnicode;
   Encoding^ u32 = Encoding::UTF32;
   
   // Encode three characters starting at index 4, and print out the counts and the resulting bytes.
   PrintCountsAndBytes( myChars, 4, 3, u7 );
   PrintCountsAndBytes( myChars, 4, 3, u8 );
   PrintCountsAndBytes( myChars, 4, 3, u16LE );
   PrintCountsAndBytes( myChars, 4, 3, u16BE );
   PrintCountsAndBytes( myChars, 4, 3, u32 );
}

void PrintCountsAndBytes( array<Char>^chars, int index, int count, Encoding^ enc )
{
   
   // Display the name of the encoding used.
   Console::Write( "{0,-30} :", enc );
   
   // Display the exact byte count.
   int iBC = enc->GetByteCount( chars, index, count );
   Console::Write( " {0,-3}", iBC );
   
   // Display the maximum byte count.
   int iMBC = enc->GetMaxByteCount( count );
   Console::Write( " {0,-3} :", iMBC );
   
   // Encode the array of chars.
   array<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 );
}

void PrintHexBytes( array<Byte>^bytes )
{
   if ( (bytes == nullptr) || (bytes->Length == 0) )
      Console::WriteLine( "<none>" );
   else
   {
      for ( int i = 0; i < bytes->Length; i++ )
         Console::Write( "{0:X2} ", bytes[ i ] );
      Console::WriteLine();
   }
}

/* 
This code produces the following output.

System.Text.UTF7Encoding       : 10  11  :2B 41 37 4C 59 2F 39 7A 2F 2D
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
System.Text.UTF32Encoding      : 8   16  :B2 03 00 00 FF FC 04 00

*/

import System.*;
import System.Text.*;

public class SamplesEncoding
{
    public static void main(String[] args)
    {
        // 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 u7 = Encoding.get_UTF7();
        Encoding u8 = Encoding.get_UTF8();
        Encoding u16LE = Encoding.get_Unicode();
        Encoding u16BE = Encoding.get_BigEndianUnicode();
        Encoding u32 = Encoding.get_UTF32();

        // Encode three characters starting at index 4, 
        // and print out the counts and the resulting bytes.
        PrintCountsAndBytes(myChars, 4, 3, u7);
        PrintCountsAndBytes(myChars, 4, 3, u8);
        PrintCountsAndBytes(myChars, 4, 3, u16LE);
        PrintCountsAndBytes(myChars, 4, 3, u16BE);
        PrintCountsAndBytes(myChars, 4, 3, u32);
    } //main

    public static void PrintCountsAndBytes(char chars[], int index,
                                            int count, Encoding enc)
    {
        // Display the name of the encoding used.
        Console.Write("{0,-30} :", enc.ToString());

        // Display the exact byte count.
        int iBC = enc.GetByteCount(chars, index, count);
        Console.Write(" {0,-3}", String.valueOf(iBC));

        // Display the maximum byte count.
        int iMBC = enc.GetMaxByteCount(count);
        Console.Write(" {0,-3} :", String.valueOf(iMBC));

        // Encode the array of chars.
        ubyte 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);
    } //PrintCountsAndBytes

    public static void PrintHexBytes(ubyte bytes[])
    {
        if(bytes == null || bytes.length == 0) {
            Console.WriteLine("<none>");
        }
        else {
            for(int i = 0; i < bytes.length; i++) {
                Console.Write("{0:X2} ",
                        ((System.Byte)bytes[i]).ToString("X2"));
            }
            Console.WriteLine();
        }
    } //PrintHexBytes
} //SamplesEncoding

/* 
This code produces the following output.

System.Text.UTF7Encoding       : 10  11  :2B 41 37 4C 59 2F 39 7A 2F 2D
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
System.Text.UTF32Encoding      : 8   16  :B2 03 00 00 FF FC 04 00

*/


Windows 98, Windows 2000 SP4, Windows Millennium Edition, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see System Requirements.

.NET Framework

Supported in: 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 2.0, 1.0

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