Encoding Class
Assembly: mscorlib (in mscorlib.dll)
[SerializableAttribute] [ComVisibleAttribute(true)] public ref class Encoding abstract : ICloneable
/** @attribute SerializableAttribute() */ /** @attribute ComVisibleAttribute(true) */ public abstract class Encoding implements ICloneable
SerializableAttribute ComVisibleAttribute(true) public abstract class Encoding implements ICloneable
Encoding is the process of transforming a set of Unicode characters into a sequence of bytes. Decoding is the reverse; it is the process of transforming a sequence of encoded bytes into a set of Unicode characters.
The Unicode Standard assigns a code point (a number) to each character in every supported script. A Unicode Transformation Format (UTF) is a way to encode that code point. The Unicode Standard version 3.2 uses the following UTFs:
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UTF-8, which represents each code point as a sequence of one to four bytes.
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UTF-16, which represents each code point as a sequence of one to two 16-bit integers.
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UTF-32, which represents each code point as a 32-bit integer.
The .NET Framework provides the following implementations of the Encoding class to support current Unicode encodings and other encodings:
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ASCIIEncoding encodes Unicode characters as single 7-bit ASCII characters. This encoding only supports character values between U+0000 and U+007F. Code page 20127. Also available through the ASCII property.
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UTF7Encoding encodes Unicode characters using the UTF-7 encoding. This encoding supports all Unicode character values. Code page 65000. Also available through the UTF7 property.
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UTF8Encoding encodes Unicode characters using the UTF-8 encoding. This encoding supports all Unicode character values. Code page 65001. Also available through the UTF8 property.
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UnicodeEncoding encodes Unicode characters using the UTF-16 encoding. Both little-endian (code page 1200) and big-endian (code page 1201) byte orders are supported. Also available through the Unicode property and the BigEndianUnicode property.
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UTF32Encoding encodes Unicode characters using the UTF-32 encoding. Both little-endian (code page 65005) and big-endian (code page 65006) byte orders are supported. Also available through the UTF32 property.
Use the GetEncoding method to obtain other encodings. Use the GetEncodings method to get a list of all encodings.
The following table lists the encodings and their associated code pages. An asterisk in the last column indicates that the code page is natively supported by the .NET Framework, regardless of the underlying platform.
| Code Page | Name | Display Name |
|
|---|---|---|---|
| 37 | IBM037 | IBM EBCDIC (US-Canada) |
|
| 437 | IBM437 | OEM United States |
|
| 500 | IBM500 | IBM EBCDIC (International) |
|
| 708 | ASMO-708 | Arabic (ASMO 708) |
|
| 720 | DOS-720 | Arabic (DOS) |
|
| 737 | ibm737 | Greek (DOS) |
|
| 775 | ibm775 | Baltic (DOS) |
|
| 850 | ibm850 | Western European (DOS) |
|
| 852 | ibm852 | Central European (DOS) |
|
| 855 | IBM855 | OEM Cyrillic |
|
| 857 | ibm857 | Turkish (DOS) |
|
| 858 | IBM00858 | OEM Multilingual Latin I |
|
| 860 | IBM860 | Portuguese (DOS) |
|
| 861 | ibm861 | Icelandic (DOS) |
|
| 862 | DOS-862 | Hebrew (DOS) |
|
| 863 | IBM863 | French Canadian (DOS) |
|
| 864 | IBM864 | Arabic (864) |
|
| 865 | IBM865 | Nordic (DOS) |
|
| 866 | cp866 | Cyrillic (DOS) |
|
| 869 | ibm869 | Greek, Modern (DOS) |
|
| 870 | IBM870 | IBM EBCDIC (Multilingual Latin-2) |
|
| 874 | windows-874 | Thai (Windows) |
|
| 875 | cp875 | IBM EBCDIC (Greek Modern) |
|
| 932 | shift_jis | Japanese (Shift-JIS) |
|
| 936 | gb2312 | Chinese Simplified (GB2312) | * |
| 949 | ks_c_5601-1987 | Korean |
|
| 950 | big5 | Chinese Traditional (Big5) |
|
| 1026 | IBM1026 | IBM EBCDIC (Turkish Latin-5) |
|
| 1047 | IBM01047 | IBM Latin-1 |
|
| 1140 | IBM01140 | IBM EBCDIC (US-Canada-Euro) |
|
| 1141 | IBM01141 | IBM EBCDIC (Germany-Euro) |
|
| 1142 | IBM01142 | IBM EBCDIC (Denmark-Norway-Euro) |
|
| 1143 | IBM01143 | IBM EBCDIC (Finland-Sweden-Euro) |
|
| 1144 | IBM01144 | IBM EBCDIC (Italy-Euro) |
|
| 1145 | IBM01145 | IBM EBCDIC (Spain-Euro) |
|
| 1146 | IBM01146 | IBM EBCDIC (UK-Euro) |
|
| 1147 | IBM01147 | IBM EBCDIC (France-Euro) |
|
| 1148 | IBM01148 | IBM EBCDIC (International-Euro) |
|
| 1149 | IBM01149 | IBM EBCDIC (Icelandic-Euro) |
|
| 1200 | utf-16 | Unicode | * |
| 1201 | unicodeFFFE | Unicode (Big-Endian) | * |
| 1250 | windows-1250 | Central European (Windows) |
|
| 1251 | windows-1251 | Cyrillic (Windows) |
|
| 1252 | Windows-1252 | Western European (Windows) | * |
| 1253 | windows-1253 | Greek (Windows) |
|
| 1254 | windows-1254 | Turkish (Windows) |
|
| 1255 | windows-1255 | Hebrew (Windows) |
|
| 1256 | windows-1256 | Arabic (Windows) |
|
| 1257 | windows-1257 | Baltic (Windows) |
|
| 1258 | windows-1258 | Vietnamese (Windows) |
|
| 1361 | Johab | Korean (Johab) |
|
| 10000 | macintosh | Western European (Mac) |
|
| 10001 | x-mac-japanese | Japanese (Mac) |
|
| 10002 | x-mac-chinesetrad | Chinese Traditional (Mac) |
|
| 10003 | x-mac-korean | Korean (Mac) | * |
| 10004 | x-mac-arabic | Arabic (Mac) |
|
| 10005 | x-mac-hebrew | Hebrew (Mac) |
|
| 10006 | x-mac-greek | Greek (Mac) |
|
| 10007 | x-mac-cyrillic | Cyrillic (Mac) |
|
| 10008 | x-mac-chinesesimp | Chinese Simplified (Mac) | * |
| 10010 | x-mac-romanian | Romanian (Mac) |
|
| 10017 | x-mac-ukrainian | Ukrainian (Mac) |
|
| 10021 | x-mac-thai | Thai (Mac) |
|
| 10029 | x-mac-ce | Central European (Mac) |
|
| 10079 | x-mac-icelandic | Icelandic (Mac) |
|
| 10081 | x-mac-turkish | Turkish (Mac) |
|
| 10082 | x-mac-croatian | Croatian (Mac) |
|
| 20000 | x-Chinese-CNS | Chinese Traditional (CNS) |
|
| 20001 | x-cp20001 | TCA Taiwan |
|
| 20002 | x-Chinese-Eten | Chinese Traditional (Eten) |
|
| 20003 | x-cp20003 | IBM5550 Taiwan |
|
| 20004 | x-cp20004 | TeleText Taiwan |
|
| 20005 | x-cp20005 | Wang Taiwan |
|
| 20105 | x-IA5 | Western European (IA5) |
|
| 20106 | x-IA5-German | German (IA5) |
|
| 20107 | x-IA5-Swedish | Swedish (IA5) |
|
| 20108 | x-IA5-Norwegian | Norwegian (IA5) |
|
| 20127 | us-ascii | US-ASCII | * |
| 20261 | x-cp20261 | T.61 |
|
| 20269 | x-cp20269 | ISO-6937 |
|
| 20273 | IBM273 | IBM EBCDIC (Germany) |
|
| 20277 | IBM277 | IBM EBCDIC (Denmark-Norway) |
|
| 20278 | IBM278 | IBM EBCDIC (Finland-Sweden) |
|
| 20280 | IBM280 | IBM EBCDIC (Italy) |
|
| 20284 | IBM284 | IBM EBCDIC (Spain) |
|
| 20285 | IBM285 | IBM EBCDIC (UK) |
|
| 20290 | IBM290 | IBM EBCDIC (Japanese katakana) |
|
| 20297 | IBM297 | IBM EBCDIC (France) |
|
| 20420 | IBM420 | IBM EBCDIC (Arabic) |
|
| 20423 | IBM423 | IBM EBCDIC (Greek) |
|
| 20424 | IBM424 | IBM EBCDIC (Hebrew) |
|
| 20833 | x-EBCDIC-KoreanExtended | IBM EBCDIC (Korean Extended) |
|
| 20838 | IBM-Thai | IBM EBCDIC (Thai) |
|
| 20866 | koi8-r | Cyrillic (KOI8-R) |
|
| 20871 | IBM871 | IBM EBCDIC (Icelandic) |
|
| 20880 | IBM880 | IBM EBCDIC (Cyrillic Russian) |
|
| 20905 | IBM905 | IBM EBCDIC (Turkish) |
|
| 20924 | IBM00924 | IBM Latin-1 |
|
| 20932 | EUC-JP | Japanese (JIS 0208-1990 and 0212-1990) |
|
| 20936 | x-cp20936 | Chinese Simplified (GB2312-80) | * |
| 20949 | x-cp20949 | Korean Wansung | * |
| 21025 | cp1025 | IBM EBCDIC (Cyrillic Serbian-Bulgarian) |
|
| 21866 | koi8-u | Cyrillic (KOI8-U) |
|
| 28591 | iso-8859-1 | Western European (ISO) | * |
| 28592 | iso-8859-2 | Central European (ISO) |
|
| 28593 | iso-8859-3 | Latin 3 (ISO) |
|
| 28594 | iso-8859-4 | Baltic (ISO) |
|
| 28595 | iso-8859-5 | Cyrillic (ISO) |
|
| 28596 | iso-8859-6 | Arabic (ISO) |
|
| 28597 | iso-8859-7 | Greek (ISO) |
|
| 28598 | iso-8859-8 | Hebrew (ISO-Visual) | * |
| 28599 | iso-8859-9 | Turkish (ISO) |
|
| 28603 | iso-8859-13 | Estonian (ISO) |
|
| 28605 | iso-8859-15 | Latin 9 (ISO) |
|
| 29001 | x-Europa | Europa |
|
| 38598 | iso-8859-8-i | Hebrew (ISO-Logical) | * |
| 50220 | iso-2022-jp | Japanese (JIS) | * |
| 50221 | csISO2022JP | Japanese (JIS-Allow 1 byte Kana) | * |
| 50222 | iso-2022-jp | Japanese (JIS-Allow 1 byte Kana - SO/SI) | * |
| 50225 | iso-2022-kr | Korean (ISO) | * |
| 50227 | x-cp50227 | Chinese Simplified (ISO-2022) | * |
| 51932 | euc-jp | Japanese (EUC) | * |
| 51936 | EUC-CN | Chinese Simplified (EUC) | * |
| 51949 | euc-kr | Korean (EUC) | * |
| 52936 | hz-gb-2312 | Chinese Simplified (HZ) | * |
| 54936 | GB18030 | Chinese Simplified (GB18030) | * |
| 57002 | x-iscii-de | ISCII Devanagari | * |
| 57003 | x-iscii-be | ISCII Bengali | * |
| 57004 | x-iscii-ta | ISCII Tamil | * |
| 57005 | x-iscii-te | ISCII Telugu | * |
| 57006 | x-iscii-as | ISCII Assamese | * |
| 57007 | x-iscii-or | ISCII Oriya | * |
| 57008 | x-iscii-ka | ISCII Kannada | * |
| 57009 | x-iscii-ma | ISCII Malayalam | * |
| 57010 | x-iscii-gu | ISCII Gujarati | * |
| 57011 | x-iscii-pa | ISCII Punjabi | * |
| 65000 | utf-7 | Unicode (UTF-7) | * |
| 65001 | utf-8 | Unicode (UTF-8) | * |
| 65005 | utf-32 | Unicode (UTF-32) | * |
| 65006 | utf-32BE | Unicode (UTF-32 Big-Endian) | * |
The GetByteCount method determines how many bytes result in encoding a set of Unicode characters, and the GetBytes method performs the actual encoding.
Likewise, the GetCharCount method determines how many characters result in decoding a sequence of bytes, and the GetChars method performs the actual decoding.
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, use the Decoder or the Encoder provided by the GetDecoder method or the GetEncoder method, respectively, of a derived class.
The UTF-16 and the UTF-32 encoders can use the big-endian byte order (most significant byte first) or the little-endian byte order (least significant byte first). For example, the Latin Capital Letter A (U+0041) is serialized as follows (in hexadecimal):
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UTF-16 big-endian byte order: 00 41
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UTF-16 little-endian byte order: 41 00
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UTF-32 big-endian byte order: 00 00 00 41
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UTF-32 little-endian byte order: 41 00 00 00
Optionally, the Encoding provides a preamble which is an array of bytes that can be prefixed to the sequence of bytes resulting from the encoding process. If the preamble contains a byte order mark (In Unicode, code point U+FEFF), it helps the decoder determine the byte order and the transformation format or UTF. The Unicode byte order mark is serialized as follows (in hexadecimal):
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UTF-8: EF BB BF
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UTF-16 big-endian byte order: FE FF
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UTF-16 little-endian byte order: FF FE
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UTF-32 big-endian byte order: 00 00 FE FF
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UTF-32 little-endian byte order: FF FE 00 00
It is generally more efficient to store Unicode characters using the native byte order. For example, it is better to use the little-endian byte order on little-endian platforms, such as Intel machines.
The GetPreamble method returns an array of bytes that can include the byte order mark. If this byte array is prefixed to an encoded stream, it helps the decoder to identify the encoding format used.
For more information on byte order and the byte order mark, see The Unicode Standard at www.unicode.org.
The following code example converts a string from one encoding to another.
using namespace System; using namespace System::Text; int main() { String^ unicodeString = "This string contains the unicode character Pi(\u03a0)"; // Create two different encodings. Encoding^ ascii = Encoding::ASCII; Encoding^ unicode = Encoding::Unicode; // Convert the string into a Byte->Item[]. array<Byte>^unicodeBytes = unicode->GetBytes( unicodeString ); // Perform the conversion from one encoding to the other. array<Byte>^asciiBytes = Encoding::Convert( unicode, ascii, unicodeBytes ); // Convert the new Byte into[] a char and[] then into a string. // This is a slightly different approach to converting to illustrate // the use of GetCharCount/GetChars. array<Char>^asciiChars = gcnew array<Char>(ascii->GetCharCount( asciiBytes, 0, asciiBytes->Length )); ascii->GetChars( asciiBytes, 0, asciiBytes->Length, asciiChars, 0 ); String^ asciiString = gcnew String( asciiChars ); // Display the strings created before and after the conversion. Console::WriteLine( "Original String*: {0}", unicodeString ); Console::WriteLine( "Ascii converted String*: {0}", asciiString ); }
package ConvertExample;
import System.*;
import System.Text.*;
class ConvertExampleClass
{
public static void main(String[] args)
{
String unicodeString =
"This string contains the unicode character Pi(\u03a0)";
// Create two different encodings.
Encoding ascii = Encoding.get_ASCII();
Encoding unicode = Encoding.get_Unicode();
// Convert the string into a byte[].
ubyte unicodeBytes[] = unicode.GetBytes(unicodeString);
// Perform the conversion from one encoding to the other.
ubyte asciiBytes[] = Encoding.Convert(unicode, ascii, unicodeBytes);
// Convert the new byte[] into a char[] and then into a string.
// This is a slightly different approach to converting to illustrate
// the use of GetCharCount/GetChars.
char asciiChars[] = new
char[ascii.GetCharCount(asciiBytes, 0, asciiBytes.length)];
ascii.GetChars(asciiBytes, 0, asciiBytes.length, asciiChars, 0);
String asciiString = new String(asciiChars);
// Display the strings created before and after the conversion.
Console.WriteLine("Original string: {0}", unicodeString);
Console.WriteLine("Ascii converted string: {0}", asciiString);
} //main
} //ConvertExampleClass
Windows 98, Windows 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see System Requirements.