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UnicodeEncoding.GetMaxCharCount Method

Calculates the maximum number of characters produced by decoding the specified number of bytes.

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

public override int GetMaxCharCount(
	int byteCount
)

Parameters

byteCount
Type: System.Int32
The number of bytes to decode.

Return Value

Type: System.Int32
The maximum number of characters produced by decoding the specified number of bytes.

ExceptionCondition
ArgumentOutOfRangeException

byteCount is less than zero.

-or-

The resulting number of bytes is greater than the maximum number that can be returned as an integer.

DecoderFallbackException

A fallback occurred (see Character Encoding in the .NET Framework for fuller explanation)

-and-

DecoderFallback is set to DecoderExceptionFallback.

To calculate the exact array size required by GetChars to store the resulting characters, the application uses GetCharCount. To calculate the maximum array size, the application should use GetMaxCharCount. The GetCharCount method generally allows allocation of less memory, while the GetMaxCharCount method generally executes faster.

GetMaxCharCount retrieves a worst-case number, including the worst case for the currently selected DecoderFallback. If a fallback is chosen with a potentially large string, GetMaxCharCount retrieves large values.

In most cases, this method retrieves reasonable numbers for small strings. For large strings, you might have to choose between using very large buffers and catching errors in the rare case that a more reasonable buffer is exceeded. You might also want to consider a different approach using GetCharCount or Convert.

GetMaxCharCount has no relation to GetBytes. If your application needs a similar function to use with GetBytes, it should use GetMaxByteCount.

NoteNote

GetMaxCharCount(N) is not necessarily the same value as N* GetMaxCharCount(1).

The following code example demonstrates how to use the GetMaxCharCount method to return the maximum number of characters produced by decoding a specified number of bytes.


using System;
using System.Text;

class UnicodeEncodingExample {
    public static void Main() {
        UnicodeEncoding Unicode = new UnicodeEncoding();
        int byteCount = 8;
        int maxCharCount = Unicode.GetMaxCharCount(byteCount);
        Console.WriteLine(
            "Maximum of {0} characters needed to decode {1} bytes.",
            maxCharCount,
            byteCount
        );
    }
}


.NET Framework

Supported in: 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Portable Class Library

Supported in: Portable Class Library

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

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

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