Parameters

s

The string containing the set of characters to encode.

charIndex

The index of the first character to encode.

charCount

The number of characters to encode.

bytes

The byte array to contain the resulting sequence of bytes.

byteIndex

The index at which to start writing the resulting sequence of bytes.

s

The string containing the set of characters to encode.

charIndex

The index of the first character to encode.

charCount

The number of characters to encode.

bytes

The byte array to contain the resulting sequence of bytes.

byteIndex

The index at which to start writing the resulting sequence of bytes.

Returns

The actual number of bytes written into bytes.

Exceptions

Type	Reason
ArgumentException	bytes does not contain sufficient space to store the encoded characters. -or- Error-checking is turned on for the current instance and chars contains an invalid surrogate sequence.
ArgumentNullException	chars or bytes is null .
ArgumentOutOfRangeException	charIndex, charCount, or byteIndex is less than zero. -or- (s.Length - charIndex) < charCount. -or- byteIndex >= bytes.Length.

Remarks

To calculate the exact array size required by UTF8Encoding.GetBytes(string, int, int, Byte[], int) to store the resulting bytes, the application uses UTF8Encoding.GetByteCount(Char[], int, int). To calculate the maximum array size, the application should use UTF8Encoding.GetMaxByteCount(int). The UTF8Encoding.GetByteCount(Char[], int, int) method generally allows allocation of less memory, while the UTF8Encoding.GetMaxByteCount(int) method generally executes faster.

With error detection, an invalid sequence causes this method to throw a ArgumentException. Without error detection, invalid sequences are ignored, and no exception is thrown.

Data to be converted, such as data read from a stream, might be available only in sequential blocks. In this case, or if the amount of data is so large that it needs to be divided into smaller blocks, the application uses the System.Text.Decoder or the System.Text.Encoder provided by the UTF8Encoding.GetDecoder method or the UTF8Encoding.GetEncoder method, respectively.

Note:

To ensure that the encoded bytes are decoded properly, the application should prefix encoded bytes with a preamble.

Requirements