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 System.Text.Decoder or the System.Text.Encoder provided by the Encoding.GetDecoder method or the Encoding.GetEncoder method, respectively, of a derived class.

The Encoding.GetByteCount(Char[]) method determines how many bytes result in encoding a set of Unicode characters, and the Encoding.GetBytes(Char[]) method performs the actual encoding. The Encoding.GetBytes(Char[]) method expects discrete conversions, in contrast to the Encoder.GetBytes(Char[], int, int, Byte[], int, bool) method, which handles multiple conversions on a single input stream.

Several versions of Encoding.GetByteCount(Char[]) and Encoding.GetBytes(Char[]) are supported. The following are some programming considerations for use of these methods:

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

• If the application handles string inputs, it is recommended to use the string version of Encoding.GetBytes(string).

• The Unicode character buffer version of Encoding.GetBytes(Char*, int, Byte*, int) allows some fast techniques, particularly with multiple calls using the System.Text.Encoder object or inserting into existing 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 Encoding.GetBytes(Char[], int, int, Byte[], int) version that supports byte arrays is the best choice.

• Consider using the erload:System.Text.Encoder.Convert method instead of Encoding.GetByteCount(Char[]). 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.

Namespace: System.Text
Assembly: mscorlib (in mscorlib.dll)
Assembly Versions: 1.0.5000.0, 2.0.0.0, 4.0.0.0