Object
Encoding
UTF8Encoding
mscorlib
BCL
Represents a UTF8 character Encoding.
UTF8Encoding encodes Unicode characters using the UTF-8 encoding (UCS Transformation Format, 8-bit form). This encoding supports all Unicode character values.[Note: UTF-8 encodes Unicode characters with a variable number of bytes per character. This encoding is optimized for the lower 127 ASCII characters, yielding an efficient mechanism to encode English in an internationalizable way. The UTF-8 identifier is the Unicode byte order mark (0xFEFF) written in UTF-8 (0xEF 0xBB 0xBF). The byte order mark is used to distinguish UTF-8 text from other encodings.
This class offers an error-checking feature that can be turned on when an instance of the class is constructed. Certain methods in this class check for invalid sequences of surrogate pairs. If error-checking is turned on and an invalid sequence is detected, ArgumentException is thrown. If error-checking is not turned on and an invalid sequence is detected, no exception is thrown and execution continues in a method-defined manner. For more information regarding surrogate pairs, see UnicodeCategory .
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System.Text Namespace
UTF8Encoding Constructors
UTF8Encoding(bool, bool) Constructor
UTF8Encoding(bool) Constructor
UTF8Encoding() Constructor
UTF8Encoding Methods
UTF8Encoding.Equals Method
UTF8Encoding.GetByteCount(System.String) Method
UTF8Encoding.GetByteCount(char[], int, int) Method
UTF8Encoding.GetBytes(System.String, int, int, byte[], int) Method
UTF8Encoding.GetBytes(System.String) Method
UTF8Encoding.GetBytes(char[], int, int, byte[], int) Method
UTF8Encoding.GetCharCount Method
UTF8Encoding.GetChars Method
UTF8Encoding.GetDecoder Method
UTF8Encoding.GetEncoder Method
UTF8Encoding.GetHashCode Method
UTF8Encoding.GetMaxByteCount Method
UTF8Encoding.GetMaxCharCount Method
UTF8Encoding.GetPreamble Method
Constructs a new instance of the UTF8Encoding class using the specified Boolean flags.
- encoderShouldEmitUTF8Identifier
- A Boolean that indicates whether the Unicode byte order mark in UTF-8 is recognized or emitted when reading from or writing to a Stream .
- throwOnInvalidBytes
- A Boolean that indicates whether error-checking is turned on for the current instance.
System.Text.UTF8Encoding Class, System.Text Namespace
Constructs a new instance of the UTF8Encoding class with the specified Boolean that indicates whether the Unicode byte order mark in UTF-8 is recognized or emitted when reading from or writing to a Stream.
- encoderShouldEmitUTF8Identifier
- A Boolean that indicates whether the Unicode byte order mark in UTF-8 is recognized or emitted when reading from or writing to a Stream .
This constructor is equivalent to UTF8Encoding (encoderShouldEmitUTF8Identifier,false).[Note: By default, this constructor turns error-checking off for the new instance.]
System.Text.UTF8Encoding Class, System.Text Namespace
Constructs a new instance of the UTF8Encoding class.
This constructor is equivalent to UTF8Encoding (false,false).[Note: By default, this constructor turns error-checking off for the new instance.]
System.Text.UTF8Encoding Class, System.Text Namespace
Determines whether the current instance and the specified Object represent the same type and value.
- value
- A Object to compare with the current instance.
trueif value is a UTF8Encoding and represents the same type and value as the current instance; otherwise,false.
[Note: This method overrides System.Object.Equals(System.Object).]
System.Text.UTF8Encoding Class, System.Text Namespace
Determines the number of bytes required to encode the characters in the specified String as a UTF8Encoding.
- chars
- A String to encode as a UTF8Encoding.
A Int32 that specifies the number of bytes necessary to encode chars as a UTF8Encoding.
Exception Type Condition ArgumentNullException chars is null.ArgumentException Error-checking is turned on for the current instance and chars contains an invalid surrogate sequence.
ArgumentOutOfRangeException The return value is greater than System.Int32.MaxValue.
If error-checking is turned off and an invalid surrogate sequence is detected, the invalid characters are ignored and do not affect the return value, and no exception is thrown.[Note: This method overrides System.Text.Encoding.GetByteCount(System.Char[]).]
System.Text.UTF8Encoding Class, System.Text Namespace
Determines the number of bytes required to encode the specified range of characters in the specified Unicode character array as a UTF8Encoding.
- chars
- The Char array to encode as a UTF8Encoding .
- index
- A Int32 that specifies the first index of chars to encode.
- count
- A Int32 that specifies the number of characters to encode.
A Int32 containing the number of bytes necessary to encode the range in chars from index to index + count - 1 as a UTF8Encoding.
Exception Type Condition ArgumentNullException chars is null.ArgumentOutOfRangeException The return value is greater than System.Int32.MaxValue. -or-
index or count is less than zero.
-or-
index and count do not specify a valid range in chars (i.e. (index + count) > chars.Length).
ArgumentException Error-checking is turned on for the current instance and chars contains an invalid surrogate sequence.
If error-checking is turned off and an invalid surrogate sequence is detected, the invalid characters are ignored and do not affect the return value, and no exception is thrown.[Note: This method overrides System.Text.Encoder.GetByteCount(System.Char[],System.Int32,System.Int32,System.Boolean) .
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System.Text.UTF8Encoding Class, System.Text Namespace
Encodes the specified range of the specified Stringinto the specified range of the specified Byte array as a UTF8Encoding .
- s
- The String to encode as a UTF8Encoding .
- charIndex
- A Int32 that specifies the first index of s to encode.
- charCount
- A Int32 that specifies the number of characters to encode.
- bytes
- The Byte array to encode into.
- byteIndex
- A Int32 that specifies the first index of bytes to encode into.
A Int32 that indicates the number of bytes encoded into bytes as a UTF8Encoding .
Exception Type Condition 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.
If error-checking is turned off and an invalid surrogate sequence is detected, the invalid characters are ignored and are not encoded into bytes, and no exception is thrown.[Note: This method overrides System.Text.Encoding.GetBytes(System.Char[]).]
System.Text.UTF8Encoding Class, System.Text Namespace
Encodes the specified String as a UTF8Encoding.
- s
- The String to encode as a UTF8Encoding.
A Byte array containing the values encoded from s as a UTF8Encoding.
Exception Type Condition ArgumentException Error-checking is turned on for the current instance and s contains an invalid surrogate sequence.
ArgumentNullException s is null.
If error-checking is turned off and an invalid surrogate sequence is detected, the invalid characters are ignored and are not encoded into the returned Byte array, and no exception is thrown.[Note: This method overrides System.Text.Encoding.GetBytes(System.Char[]).]
System.Text.UTF8Encoding Class, System.Text Namespace
Encodes the specified range of the specified Char array into the specified range of the specified Byte array as a UTF8Encoding.
- chars
- The Char array to encode as a UTF8Encoding .
- charIndex
- A Int32 that specifies the first index of chars to encode.
- charCount
- A Int32 that specifies the number of characters to encode.
- bytes
- The Byte array to encode into.
- byteIndex
- A Int32 that specifies the first index of bytes to encode into.
A Int32 that indicates the number of bytes encoded into bytes as a UTF8Encoding.
Exception Type Condition 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-
(chars.Length - charIndex) < charCount.
-or-
byteIndex > bytes.Length.
If error-checking is turned off and an invalid surrogate sequence is detected, the invalid characters are ignored and are not encoded into bytes, and no exception is thrown.[Note: This method overrides System.Text.Encoding.GetBytes(System.Char[]).
System.Text.UTF8Encoding.GetByteCount(System.Char[],System.Int32,System.Int32) can be used to determine the exact number of bytes that will be produced for a given range of characters. Alternatively, System.Text.UTF8Encoding.GetMaxByteCount(System.Int32) can be used to determine the maximum number of bytes that will be produced for a specified number of characters, regardless of the actual character values.
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System.Text.UTF8Encoding Class, System.Text Namespace
Returns the number of characters produced by decoding the specified range of the specified Byte array as a UTF8Encoding .
- bytes
- The Byte array to decode as a UTF8Encoding .
- index
- A Int32 that specifies the first index of bytes to decode.
- count
- A Int32 that specifies the number of bytes to decode.
A Int32 that indicates the number of characters produced by decoding the range in bytes from index to index + count - 1 as a UTF8Encoding .
Exception Type Condition ArgumentNullException bytes is null.ArgumentOutOfRangeException index or count is less than zero. -or-
index and count do not specify a valid range in bytes (i.e. (index + count) > bytes.Length).
ArgumentException Error-checking is turned on for the current instance and bytes contains an invalid surrogate sequence.
If error-checking is turned off and an invalid surrogate sequence is detected, the invalid bytes are ignored and do not affect the return value, and no exception is thrown.[Note: This method overrides System.Text.Encoding.GetCharCount(System.Byte[]).]
System.Text.UTF8Encoding Class, System.Text Namespace
Decodes the specified range of the specified Byte array into the specified range of the specified Char array as a UTF8Encoding .
- bytes
- The Byte array to decode as a UTF8Encoding .
- byteIndex
- A Int32 that specifies the first index of bytes to decode.
- byteCount
- A Int32 that specifies the number of bytes to decode.
- chars
- The Char array to decode into.
- charIndex
- A Int32 that specifies the first index of chars to decode into.
The number of characters decoded into chars as a UTF8Encoding .
Exception Type Condition ArgumentException chars does not contain sufficient space to store the decoded characters. -or-
Error-checking is turned on for the current instance and bytes contains an invalid surrogate sequence.
ArgumentNullException bytes or chars is null.
ArgumentOutOfRangeException byteIndex, byteCount, or charIndex is less than zero. -or-
(bytes.Length - byteIndex) < byteCount.
-or-
charIndex > chars.Length.
If error-checking is turned off and an invalid surrogate sequence is detected, the invalid bytes are ignored and are not encoded into chars, and no exception is thrown.[Note: This method overrides System.Text.Encoding.GetChars(System.Byte[]) .
System.Text.UTF8Encoding.GetCharCount(System.Byte[],System.Int32,System.Int32) can be used to determine the exact number of characters that will be produced for a specified range of bytes. Alternatively, System.Text.UTF8Encoding.GetMaxCharCount(System.Int32) can be used to determine the maximum number of characters that will be produced for a specified number of bytes, regardless of the actual byte values.
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System.Text.UTF8Encoding Class, System.Text Namespace
Returns a Decoder for the current instance.
A Decoder for the current instance.
[Note: This method overrides System.Text.Encoding.GetDecoder .Contrary to System.Text.UTF8Encoding.GetChars(System.Byte[],System.Int32,System.Int32,System.Char[],System.Int32) , a decoder can convert partial sequences of bytes into partial sequences of characters by maintaining the appropriate state between the conversions.
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System.Text.UTF8Encoding Class, System.Text Namespace
Returns a Encoder for the current instance.
A Encoder for the current instance.
[Note: This method overrides System.Text.Encoding.GetEncoder.Contrary to System.Text.UTF8Encoding.GetBytes(System.Char[],System.Int32,System.Int32,System.Byte[],System.Int32) , an encoder can convert partial sequences of characters into partial sequences of bytes by maintaining the appropriate state between the conversions.
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System.Text.UTF8Encoding Class, System.Text Namespace
Generates a hash code for the current instance.
A Int32 value containing a hash code for the current instance
The algorithm used to generate the hash code is unspecified.[Note: This method overrides System.Object.GetHashCode.]
System.Text.UTF8Encoding Class, System.Text Namespace
Returns the maximum number of bytes required to encode the specified number of characters as a UTF8Encoding, regardless of the actual character values.
- charCount
- A Int32 that specifies the number of characters to encode as a UTF8Encoding .
A Int32 that specifies the maximum number of bytes required to encode charCount characters as a UTF8Encoding .
Exception Type Condition ArgumentOutOfRangeException charCount < 0.
[Note: This method overrides System.Text.Encoding.GetMaxByteCount(System.Int32) .This method can be used to determine an appropriate buffer size for byte arrays passed to System.Text.UTF8Encoding.GetBytes(System.Char[],System.Int32,System.Int32,System.Byte[],System.Int32). Using this minimum buffer size can help ensure that no buffer overflow exceptions will occur.
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System.Text.UTF8Encoding Class, System.Text Namespace
Returns the maximum number of characters produced by decoding the specified number of bytes as a UTF8Encoding, regardless of the actual byte values.
- byteCount
- A Int32 that specifies the number of bytes to decode as a UTF8Encoding .
A Int32 that specifies the maximum number of characters produced by decoding byteCount bytes as a UTF8Encoding .
Exception Type Condition ArgumentOutOfRangeException byteCount < 0.
[Note: This method overrides System.Text.Encoding.GetMaxCharCount(System.Int32) .This method can be used to determine an appropriate minimum buffer size for character arrays passed to System.Text.UTF8Encoding.GetChars(System.Byte[],System.Int32,System.Int32,System.Char[],System.Int32) . Using this minimum buffer size can help ensure that no buffer overflow exceptions will occur.
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System.Text.UTF8Encoding Class, System.Text Namespace
Returns the bytes used at the beginning of a stream to determine which encoding a file was created with.
A Byte array containing the UTF-8 encoding preamble.
[Note: This method overrides System.Text.Encoding.GetPreamble .System.Text.UTF8Encoding.GetPreamble returns the Unicode byte order mark (U+FEFF) written in UTF-8 (0xef, 0xbb, 0xbf) if this instance was constructed with a request to emit the UTF-8 identifier.
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System.Text.UTF8Encoding Class, System.Text Namespace