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Decoder.GetChars Method (Byte[], Int32, Int32, Char[], Int32)

When overridden in a derived class, decodes a sequence of bytes from the specified byte array and any bytes in the internal buffer into the specified character array.

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

public abstract int GetChars (
	byte[] bytes,
	int byteIndex,
	int byteCount,
	char[] chars,
	int charIndex
public abstract int GetChars (
	byte[] bytes, 
	int byteIndex, 
	int byteCount, 
	char[] chars, 
	int charIndex
public abstract function GetChars (
	bytes : byte[], 
	byteIndex : int, 
	byteCount : int, 
	chars : char[], 
	charIndex : int
) : int
Not applicable.



The byte array containing the sequence of bytes to decode.


The index of the first byte to decode.


The number of bytes to decode.


The character array to contain the resulting set of characters.


The index at which to start writing the resulting set of characters.

Return Value

The actual number of characters written into chars.

Exception typeCondition


bytes is a null reference (Nothing in Visual Basic)(Nothing).


chars is a null reference (Nothing in Visual Basic)(Nothing).


byteIndex or byteCount or charIndex is less than zero.


byteindex and byteCount do not denote a valid range in bytes.


charIndex is not a valid index in chars.


chars does not have enough capacity from charIndex to the end of the array to accommodate the resulting characters.


A fallback occurred (see Understanding Encodings for fuller explanation)


Fallback is set to DecoderExceptionFallback.

Remember that the Decoder object saves state between calls to GetChars. When the application is done with a stream of data, it should set the flush parameter to true to make sure that the state information is flushed. With this setting, the decoder ignores invalid bytes at the end of the data block and clears the internal buffer.

To calculate the exact array size that GetChars requires to store the resulting characters, the application should use GetCharCount.

If GetChars is called with flush set to false, the decoder stores trailing bytes at the end of the data block in an internal buffer and uses them in the next decoding operation. The application should call GetCharCount on a block of data immediately before calling GetChars on the same block, so that any trailing bytes from the previous block are included in the calculation.

The following example demonstrates how to decode a range of elements from a byte array and store them in a Unicode character array. The GetCharCount method is used to calculate the number of characters needed to store the decoded elements in the array bytes. The GetChars method decodes the specified elements in the byte array and stores them in the new character array.

using System;
using System.Text;

class UnicodeEncodingExample {
    public static void Main() {
        Char[] chars;
        Byte[] bytes = new Byte[] {
            85, 0, 110, 0, 105, 0, 99, 0, 111, 0, 100, 0, 101, 0

        Decoder uniDecoder = Encoding.Unicode.GetDecoder();

        int charCount = uniDecoder.GetCharCount(bytes, 0, bytes.Length);
        chars = new Char[charCount];
        int charsDecodedCount = uniDecoder.GetChars(bytes, 0, bytes.Length, chars, 0);

            "{0} characters used to decode bytes.", charsDecodedCount

        Console.Write("Decoded chars: ");
        foreach (Char c in chars) {
            Console.Write("[{0}]", c);

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

class UnicodeEncodingExample
    public static void main(String[] args)
        char chars[];
        ubyte bytes[] = new ubyte[] {
            85, 0, 110, 0, 105, 0, 99, 0, 111, 0, 100, 0, 101, 0};
        Decoder uniDecoder = Encoding.get_Unicode().GetDecoder();
        int charCount = uniDecoder.GetCharCount(bytes, 0, bytes.length);
        chars = new char[charCount];
        int charsDecodedCount = uniDecoder.GetChars(bytes,
                                0, bytes.length, chars, 0);
        Console.WriteLine("{0} characters used to decode bytes.", 
        Console.Write("Decoded chars: ");
        for(int iCtr = 0; iCtr < chars.length; iCtr++) {
            char c = chars[iCtr];
            Console.Write("[{0}]", String.valueOf(c));
    } //main
} //UnicodeEncodingExample

Windows 98, Windows Server 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.

.NET Framework

Supported in: 3.0, 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 2.0, 1.0

XNA Framework

Supported in: 1.0

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