UTF7Encoding Class
Assembly: mscorlib (in mscorlib.dll)
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.
 Caution |
|---|
| UTF7Encoding does not provide error detection. For security reasons, it is recommended that you use UTF8Encoding, UnicodeEncoding, or UTF32Encoding and enable error detection. |
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.
UTF7Encoding corresponds to the Windows code page 65000.
| Note |
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| The state of a UTF-7 encoded object is not preserved if the object is serialized and deserialized using different .NET Framework versions. |
The following code example demonstrates how to use a UTF7Encoding to encode a string of Unicode characters and store them in a byte array. Notice that when the byte array is decoded back to a string, no data is lost.
using System; using System.Text; class UTF7EncodingExample { public static void Main() { // Create a UTF-7 encoding. UTF7Encoding utf7 = new UTF7Encoding(); // A Unicode string with two characters outside a 7-bit code range. String unicodeString = "This Unicode string contains two characters " + "with codes outside a 7-bit code range, " + "Pi (\u03a0) and Sigma (\u03a3)."; Console.WriteLine("Original string:"); Console.WriteLine(unicodeString); // Encode the string. Byte[] encodedBytes = utf7.GetBytes(unicodeString); Console.WriteLine(); Console.WriteLine("Encoded bytes:"); foreach (Byte b in encodedBytes) { Console.Write("[{0}]", b); } Console.WriteLine(); // Decode bytes back to string. // Notice Pi and Sigma characters are still present. String decodedString = utf7.GetString(encodedBytes); Console.WriteLine(); Console.WriteLine("Decoded bytes:"); Console.WriteLine(decodedString); } }
import System.*;
import System.Text.*;
class UTF7EncodingExample
{
public static void main(String[] args)
{
// Create a UTF-7 encoding.
UTF7Encoding utf7 = new UTF7Encoding();
// A Unicode string with two characters outside a 7-bit code range.
String unicodeString = "This Unicode string contains two characters "
+ "with codes outside a 7-bit code range, "
+ "Pi (\u03a0) and Sigma (\u03a3).";
Console.WriteLine("Original string:");
Console.WriteLine(unicodeString);
// Encode the string.
ubyte encodedBytes[] = utf7.GetBytes(unicodeString);
Console.WriteLine();
Console.WriteLine("Encoded bytes:");
for(int iCtr = 0; iCtr < encodedBytes.length; iCtr++) {
ubyte b = encodedBytes[iCtr];
Console.Write("[{0}]", String.valueOf(b));
}
Console.WriteLine();
// Decode bytes back to string.
// Notice Pi and Sigma characters are still present.
String decodedString = utf7.GetString(encodedBytes);
Console.WriteLine();
Console.WriteLine("Decoded bytes:");
Console.WriteLine(decodedString);
} //main
} //UTF7EncodingExample
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.
