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GetChars Method (Byte*, Int32, Char*, Int32)

Encoding.GetChars Method (Byte*, Int32, Char*, Int32)

When overridden in a derived class, decodes a sequence of bytes starting at the specified byte pointer into a set of characters that are stored starting at the specified character pointer.

This API is not CLS-compliant. 

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

[ComVisibleAttribute(false)]
[CLSCompliantAttribute(false)]
public virtual int GetChars(
	byte* bytes,
	int byteCount,
	char* chars,
	int charCount
)

Parameters

bytes
Type: System.Byte*

A pointer to the first byte to decode.

byteCount
Type: System.Int32

The number of bytes to decode.

chars
Type: System.Char*

A pointer to the location at which to start writing the resulting set of characters.

charCount
Type: System.Int32

The maximum number of characters to write.

Return Value

Type: System.Int32
The actual number of characters written at the location indicated by the chars parameter.

ExceptionCondition
ArgumentNullException

bytes is null.

-or-

chars is null.

ArgumentOutOfRangeException

byteCount or charCount is less than zero.

ArgumentException

charCount is less than the resulting number of characters.

DecoderFallbackException

A fallback occurred (see Understanding Encodings for complete explanation)

-and-

DecoderFallback is set to DecoderExceptionFallback.

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

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 object provided by the GetDecoder or the GetEncoder method, respectively, of a derived class.

Note   This method is intended to operate on Unicode characters, not on arbitrary binary data, such as byte arrays. If your application needs to encode arbitrary binary data into text, it should use a protocol such as uuencode, which is implemented by methods such as Convert.ToBase64CharArray.

The GetCharCount method determines how many characters result in decoding a sequence of bytes, and the GetChars method performs the actual decoding. The Encoding.GetChars method expects discrete conversions, in contrast to the Decoder.GetChars method, which handles multiple passes on a single input stream.

Several versions of GetCharCount and GetChars are supported. The following are some programming considerations for use of these methods:

  • The application might need to decode multiple input bytes from a code page and process the bytes using multiple calls. In this case, your application probably needs to maintain state between calls.

  • If the application handles string outputs, it is recommended to use the GetString method. Since this method must check string length and allocate a buffer, it is slightly slower, but the resulting String type is to be preferred.

  • The byte version of GetChars allows some fast techniques, particularly with multiple calls to large buffers. Bear in mind, however, that this method version is sometimes unsafe, since pointers are required.

  • If your application must convert a large amount of data, it should reuse the output buffer. In this case, the GetChars version that supports output character buffers is the best choice.

  • Consider using the Decoder.Convert method instead of GetCharCount. The conversion method converts as much data as possible and throws an exception if the output buffer is too small. For continuous decoding of a stream, this method is often the best choice.

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98

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

.NET Framework

Supported in: 3.5, 3.0, 2.0

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