Decoder.GetCharCount Method (Byte[], Int32, Int32)

When overridden in a derived class, calculates the number of characters produced by decoding a sequence of bytes from the specified byte array.

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

public abstract int GetCharCount (
	byte[] bytes,
	int index,
	int count
)
public abstract int GetCharCount (
	byte[] bytes, 
	int index, 
	int count
)
public abstract function GetCharCount (
	bytes : byte[], 
	index : int, 
	count : int
) : int
Not applicable.

Parameters

bytes

The byte array containing the sequence of bytes to decode.

index

The index of the first byte to decode.

count

The number of bytes to decode.

Return Value

The number of characters produced by decoding the specified sequence of bytes and any bytes in the internal buffer.

Exception typeCondition

ArgumentNullException

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

ArgumentOutOfRangeException

index or count is less than zero.

-or-

index and count do not denote a valid range in bytes.

DecoderFallbackException

A fallback occurred (see Understanding Encodings for fuller explanation)

-and-

Fallback is set to DecoderExceptionFallback.

This method does not affect the state of the decoder.

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 code example demonstrates how to use the GetCharCount method to calculate the number of characters required to decode the specified range of bytes in the array.

using System;
using System.Text;

class DecoderExample {
    public static void Main() {
        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);
        Console.WriteLine(
            "{0} characters needed to decode bytes.", charCount
        );
    }
}

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

class DecoderExample
{
    public static void main(String[] args)
    {
        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);
        Console.WriteLine("{0} characters needed to decode bytes.", 
            String.valueOf(charCount));
    } //main
} //DecoderExample

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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