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

 

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

This API is not CLS-compliant.

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

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

Parameters

chars
Type: System.Char*

A pointer to the first character to encode.

charCount
Type: System.Int32

The number of characters to encode.

bytes
Type: System.Byte*

A pointer to the location at which to start writing the resulting sequence of bytes.

byteCount
Type: System.Int32

The maximum number of bytes to write.

Return Value

Type: System.Int32

The actual number of bytes written at the location indicated by the bytes parameter.

Exception Condition
ArgumentNullException

chars is null.

-or-

bytes is null.

ArgumentOutOfRangeException

charCount or byteCount is less than zero.

ArgumentException

byteCount is less than the resulting number of bytes.

EncoderFallbackException

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

-and-

EncoderFallback is set to EncoderExceptionFallback.

To calculate the exact array size that GetBytes requires to store the resulting bytes, call the GetByteCount method. To calculate the maximum array size, call the GetMaxByteCount method. The GetByteCount method generally allows allocation of less memory, while the GetMaxByteCount 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, you should use the Decoder or the Encoder object provided by the GetDecoder or the GetEncoder method, respectively, of a derived class.

The GetByteCount method determines how many bytes result in encoding a set of Unicode characters, and the GetBytes method performs the actual encoding. The GetBytes method expects discrete conversions, in contrast to the Encoder.GetBytes method, which handles multiple conversions on a single input stream.

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

  • Your app might need to encode many input characters to a code page and process the characters using multiple calls. In this case, you probably need to maintain state between calls, taking into account the state that is persisted by the Encoder object being used. (For example, a character sequence that includes surrogate pairs might end with a high surrogate. The Encoder will remember that high surrogate so that it can be combined with a low surrogate at the beginning of a following call. Encoding won't be able to maintain the state, so the character will be sent to the EncoderFallback.)

  • If your app handles string inputs, you should use the string version of GetBytes.

  • The Unicode character buffer version of GetBytes(Char*, Int32, Byte*, Int32) allows some fast techniques, particularly with multiple calls using the Encoder object or inserting into existing buffers. Bear in mind, however, that this method version is sometimes unsafe, since pointers are required.

  • If your app must convert a large amount of data, it should reuse the output buffer. In this case, the GetBytes version that supports byte arrays is the best choice.

  • Consider using the Encoder.Convert method instead of GetByteCount. The conversion method converts as much data as possible, and does throw an exception if the output buffer is too small. For continuous encoding of a stream, this method is often the best choice.

SecurityCriticalAttribute

Requires full trust for the immediate caller. This member cannot be used by partially trusted or transparent code.

Universal Windows Platform
Available since 10
.NET Framework
Available since 2.0
Silverlight
Available since 2.0
Windows Phone Silverlight
Available since 7.0
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