UTF8Encoding Class
[ This article is for Windows Phone 8 developers. If you’re developing for Windows 10, see the latest documentation. ]
Represents a UTF-8 encoding of Unicode characters.
Assembly: mscorlib (in mscorlib.dll)
The UTF8Encoding type exposes the following members.
| Name | Description | |
|---|---|---|
 | UTF8Encoding() | Initializes a new instance of the UTF8Encoding class. |
| UTF8Encoding(Boolean) | Initializes a new instance of the UTF8Encoding class. A parameter specifies whether to provide a Unicode byte order mark. |
| UTF8Encoding(Boolean, Boolean) | Initializes a new instance of the UTF8Encoding class. Parameters specify whether to provide a Unicode byte order mark and whether to throw an exception when an invalid encoding is detected. |
| Name | Description | |
|---|---|---|
| Clone | When overridden in a derived class, creates a shallow copy of the current Encoding object. (Inherited from Encoding.) |
| Equals | Determines whether the specified Object is equal to the current UTF8Encoding object. (Overrides Encoding::Equals(Object).) |
 | Finalize | Allows an object to try to free resources and perform other cleanup operations before the Object is reclaimed by garbage collection. (Inherited from Object.) |
| GetByteCount(array<Char>) | When overridden in a derived class, calculates the number of bytes produced by encoding all the characters in the specified character array. (Inherited from Encoding.) |
| GetByteCount(String) | Calculates the number of bytes that would be produced by encoding the characters in the specified String. (Overrides Encoding::GetByteCount(String).) |
| GetByteCount(array<Char>, Int32, Int32) | Calculates the number of bytes that would be produced by encoding a set of characters from the specified character array. (Overrides Encoding::GetByteCount(array<Char>, Int32, Int32).) |
| GetBytes(array<Char>) | When overridden in a derived class, encodes all the characters in the specified character array into a sequence of bytes. (Inherited from Encoding.) |
| GetBytes(String) | When overridden in a derived class, encodes all the characters in the specified string into a sequence of bytes. (Inherited from Encoding.) |
| GetBytes(array<Char>, Int32, Int32) | When overridden in a derived class, encodes a set of characters from the specified character array into a sequence of bytes. (Inherited from Encoding.) |
| GetBytes(Char*, Int32, Byte*, Int32) | Security Critical. 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. (Overrides Encoding::GetBytes(Char*, Int32, Byte*, Int32).) |
| GetBytes(array<Char>, Int32, Int32, array<Byte>, Int32) | Encodes a set of characters from the specified character array into the specified byte array. (Overrides Encoding::GetBytes(array<Char>, Int32, Int32, array<Byte>, Int32).) |
| GetBytes(String, Int32, Int32, array<Byte>, Int32) | Encodes a set of characters from the specified string into the specified byte array. (Overrides Encoding::GetBytes(String, Int32, Int32, array<Byte>, Int32).) |
| GetCharCount(array<Byte>) | When overridden in a derived class, calculates the number of characters produced by decoding all the bytes in the specified byte array. (Inherited from Encoding.) |
| GetCharCount(array<Byte>, Int32, Int32) | Calculates the number of characters produced by decoding a sequence of bytes from the specified byte array. (Overrides Encoding::GetCharCount(array<Byte>, Int32, Int32).) |
| GetChars(array<Byte>) | When overridden in a derived class, decodes all the bytes in the specified byte array into a set of characters. (Inherited from Encoding.) |
| GetChars(array<Byte>, Int32, Int32) | When overridden in a derived class, decodes a sequence of bytes from the specified byte array into a set of characters. (Inherited from Encoding.) |
| GetChars(array<Byte>, Int32, Int32, array<Char>, Int32) | Decodes a sequence of bytes from the specified byte array into the specified character array. (Overrides Encoding::GetChars(array<Byte>, Int32, Int32, array<Char>, Int32).) |
| GetDecoder | Obtains a decoder that converts a UTF-8 encoded sequence of bytes into a sequence of Unicode characters. (Overrides Encoding::GetDecoder().) |
| GetEncoder | Obtains an encoder that converts a sequence of Unicode characters into a UTF-8 encoded sequence of bytes. (Overrides Encoding::GetEncoder().) |
| GetHashCode | Returns the hash code for the current instance. (Overrides Encoding::GetHashCode().) |
| GetMaxByteCount | Calculates the maximum number of bytes produced by encoding the specified number of characters. (Overrides Encoding::GetMaxByteCount(Int32).) |
| GetMaxCharCount | Calculates the maximum number of characters produced by decoding the specified number of bytes. (Overrides Encoding::GetMaxCharCount(Int32).) |
| GetPreamble | Returns a Unicode byte order mark encoded in UTF-8 format. (Overrides Encoding::GetPreamble().) |
| GetString | Decodes a range of bytes from a byte array into a string. (Overrides Encoding::GetString(array<Byte>, Int32, Int32).) |
| GetType | Gets the Type of the current instance. (Inherited from Object.) |
| MemberwiseClone | Creates a shallow copy of the current Object. (Inherited from Object.) |
| ToString | Returns a string that represents the current object. (Inherited from Object.) |
Encoding is the process of transforming a set of Unicode characters into a sequence of bytes. Decoding is the process of transforming a sequence of encoded bytes into a set of Unicode characters. UTF-8 encoding represents each code point as a sequence of one to four bytes.
You can instantiate a UTF8Encoding object in any of the following ways:
By retrieving the UTF8Encoding object returned by the UTF8 property.
By calling the GetEncoding method with "utf-8" as the value of its name parameter.
By calling one of the overloads of the UTF8Encoding class constructor. Unlike the other ways to instantiate a UTF8Encoding object, which return a default UTF8Encoding object, overloads of the class constructor allow you to define whether encodings include a preamble and whether an exception is thrown if an invalid encoding is encountered.
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 and GetString methods perform the actual decoding.
Optionally, the UTF8Encoding object 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 (BOM), it helps the decoder determine the byte order and the transformation format or UTF. The GetPreamble method retrieves an array of bytes that can include the BOM. For more information on byte order and the byte order mark, see The Unicode Standard at the Unicode home page.
 Note: |
|---|
To enable error detection and to make the class instance more secure, the application should use the UTF8Encoding constructor that takes a throwOnInvalidBytes parameter and set that parameter to true. With error detection, a method that detects an invalid sequence of characters or bytes throws a ArgumentException. Without error detection, no exception is thrown, and the invalid sequence is generally ignored. |