UTF7Encoding Class

Definition

Namespace:

System.Text

Assembly:

System.Text.Encoding.Extensions.dll

Source:

UTF7Encoding.cs

Represents a UTF-7 encoding of Unicode characters.

public ref class UTF7Encoding : System::Text::Encoding

public class UTF7Encoding : System.Text.Encoding

type UTF7Encoding = class
    inherit Encoding

Public Class UTF7Encoding
Inherits Encoding

Inheritance

Object

Encoding

UTF7Encoding

Examples

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 namespace System;
using namespace System::Text;
using namespace System::Collections;
int main()
{
   
   // Create a UTF-7 encoding.
   UTF7Encoding^ utf7 = gcnew UTF7Encoding;
   
   // A Unicode string with two characters outside a 7-bit code range.
   String^ unicodeString = L"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.
   array<Byte>^encodedBytes = utf7->GetBytes( unicodeString );
   Console::WriteLine();
   Console::WriteLine( "Encoded bytes:" );
   IEnumerator^ myEnum = encodedBytes->GetEnumerator();
   while ( myEnum->MoveNext() )
   {
      Byte b = safe_cast<Byte>(myEnum->Current);
      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 );
}

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);
    }
}

Imports System.Text
Imports Microsoft.VisualBasic.Strings

Class UTF7EncodingExample
    
    Public Shared Sub Main()
        ' Create a UTF-7 encoding.
        Dim utf7 As New UTF7Encoding()
        
        ' A Unicode string with two characters outside a 7-bit code range.
        Dim unicodeString As String = _
            "This Unicode string contains two characters " & _
            "with codes outside a 7-bit code range, " & _
            "Pi (" & ChrW(928) & ") and Sigma (" & ChrW(931) & ")."
        Console.WriteLine("Original string:")
        Console.WriteLine(unicodeString)
        
        ' Encode the string.
        Dim encodedBytes As Byte() = utf7.GetBytes(unicodeString)
        Console.WriteLine()
        Console.WriteLine("Encoded bytes:")
        Dim b As Byte
        For Each b In  encodedBytes
            Console.Write("[{0}]", b)
        Next b
        Console.WriteLine()
        
        ' Decode bytes back to string.
        ' Notice Pi and Sigma characters are still present.
        Dim decodedString As String = utf7.GetString(encodedBytes)
        Console.WriteLine()
        Console.WriteLine("Decoded bytes:")
        Console.WriteLine(decodedString)
    End Sub
End Class

Remarks

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.

The UTF-7 encoding represents Unicode characters as sequences of 7-bit ASCII characters. This encoding supports certain protocols for which it is required, most often email or newsgroup protocols. Since UTF-7 is not particularly secure or robust, and most modern systems allow 8-bit encodings, UTF-8 should normally be preferred to UTF-7.

Note

UTF7Encoding does not provide error detection. For security reasons, the application should use UTF8Encoding, UnicodeEncoding, or UTF32Encoding and enable error detection.

For more information about the UTFs and other encodings supported by System.Text, see Character Encoding in the .NET Framework.

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

The state of a UTF-7 encoded object is not preserved if the object is serialized and deserialized using different .NET Framework versions.

Constructors

UTF7Encoding()	Obsolete. Initializes a new instance of the UTF7Encoding class.
UTF7Encoding(Boolean)	Obsolete. Initializes a new instance of the UTF7Encoding class. A parameter specifies whether to allow optional characters.

Properties

BodyName	When overridden in a derived class, gets a name for the current encoding that can be used with mail agent body tags. (Inherited from Encoding)
CodePage	When overridden in a derived class, gets the code page identifier of the current Encoding. (Inherited from Encoding)
DecoderFallback	Gets or sets the DecoderFallback object for the current Encoding object. (Inherited from Encoding)
EncoderFallback	Gets or sets the EncoderFallback object for the current Encoding object. (Inherited from Encoding)
EncodingName	When overridden in a derived class, gets the human-readable description of the current encoding. (Inherited from Encoding)
HeaderName	When overridden in a derived class, gets a name for the current encoding that can be used with mail agent header tags. (Inherited from Encoding)
IsBrowserDisplay	When overridden in a derived class, gets a value indicating whether the current encoding can be used by browser clients for displaying content. (Inherited from Encoding)
IsBrowserSave	When overridden in a derived class, gets a value indicating whether the current encoding can be used by browser clients for saving content. (Inherited from Encoding)
IsMailNewsDisplay	When overridden in a derived class, gets a value indicating whether the current encoding can be used by mail and news clients for displaying content. (Inherited from Encoding)
IsMailNewsSave	When overridden in a derived class, gets a value indicating whether the current encoding can be used by mail and news clients for saving content. (Inherited from Encoding)
IsReadOnly	When overridden in a derived class, gets a value indicating whether the current encoding is read-only. (Inherited from Encoding)
IsSingleByte	When overridden in a derived class, gets a value indicating whether the current encoding uses single-byte code points. (Inherited from Encoding)
Preamble	When overridden in a derived class, returns a span containing the sequence of bytes that specifies the encoding used. (Inherited from Encoding)
WebName	When overridden in a derived class, gets the name registered with the Internet Assigned Numbers Authority (IANA) for the current encoding. (Inherited from Encoding)
WindowsCodePage	When overridden in a derived class, gets the Windows operating system code page that most closely corresponds to the current encoding. (Inherited from Encoding)

Methods

Clone()	When overridden in a derived class, creates a shallow copy of the current Encoding object. (Inherited from Encoding)
Equals(Object)	Gets a value indicating whether the specified object is equal to the current UTF7Encoding object.
GetByteCount(Char[], Int32, Int32)	Calculates the number of bytes produced by encoding a set of characters from the specified character array.
GetByteCount(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(Char*, Int32)	Calculates the number of bytes produced by encoding a set of characters starting at the specified character pointer.
GetByteCount(ReadOnlySpan<Char>)	When overridden in a derived class, calculates the number of bytes produced by encoding the characters in the specified character span. (Inherited from Encoding)
GetByteCount(String, Int32, Int32)	When overridden in a derived class, calculates the number of bytes produced by encoding a set of characters from the specified string. (Inherited from Encoding)
GetByteCount(String)	Calculates the number of bytes produced by encoding the characters in the specified String object.
GetBytes(Char[], Int32, Int32, Byte[], Int32)	Encodes a set of characters from the specified character array into the specified byte array.
GetBytes(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[])	When overridden in a derived class, encodes all the characters in the specified character array into a sequence of bytes. (Inherited from Encoding)
GetBytes(Char*, Int32, Byte*, Int32)	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.
GetBytes(ReadOnlySpan<Char>, Span<Byte>)	When overridden in a derived class, encodes into a span of bytes a set of characters from the specified read-only span. (Inherited from Encoding)
GetBytes(String, Int32, Int32, Byte[], Int32)	Encodes a set of characters from the specified String into the specified byte array.
GetBytes(String, Int32, Int32)	When overridden in a derived class, encodes into an array of bytes the number of characters specified by count in the specified string, starting from the specified index. (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)
GetCharCount(Byte[], Int32, Int32)	Calculates the number of characters produced by decoding a sequence of bytes from the specified byte array.
GetCharCount(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(Byte*, Int32)	Calculates the number of characters produced by decoding a sequence of bytes starting at the specified byte pointer.
GetCharCount(ReadOnlySpan<Byte>)	When overridden in a derived class, calculates the number of characters produced by decoding the provided read-only byte span. (Inherited from Encoding)
GetChars(Byte[], Int32, Int32, Char[], Int32)	Decodes a sequence of bytes from the specified byte array into the specified character array.
GetChars(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(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(Byte*, Int32, Char*, Int32)	Decodes a sequence of bytes starting at the specified byte pointer into a set of characters that are stored starting at the specified character pointer.
GetChars(ReadOnlySpan<Byte>, Span<Char>)	When overridden in a derived class, decodes all the bytes in the specified read-only byte span into a character span. (Inherited from Encoding)
GetDecoder()	Obtains a decoder that converts a UTF-7 encoded sequence of bytes into a sequence of Unicode characters.
GetEncoder()	Obtains an encoder that converts a sequence of Unicode characters into a UTF-7 encoded sequence of bytes.
GetHashCode()	Returns the hash code for the current UTF7Encoding object.
GetMaxByteCount(Int32)	Calculates the maximum number of bytes produced by encoding the specified number of characters.
GetMaxCharCount(Int32)	Calculates the maximum number of characters produced by decoding the specified number of bytes.
GetPreamble()	When overridden in a derived class, returns a sequence of bytes that specifies the encoding used. (Inherited from Encoding)
GetString(Byte[], Int32, Int32)	Decodes a range of bytes from a byte array into a string.
GetString(Byte[])	When overridden in a derived class, decodes all the bytes in the specified byte array into a string. (Inherited from Encoding)
GetString(Byte*, Int32)	When overridden in a derived class, decodes a specified number of bytes starting at a specified address into a string. (Inherited from Encoding)
GetString(ReadOnlySpan<Byte>)	When overridden in a derived class, decodes all the bytes in the specified byte span into a string. (Inherited from Encoding)
GetType()	Gets the Type of the current instance. (Inherited from Object)
IsAlwaysNormalized()	Gets a value indicating whether the current encoding is always normalized, using the default normalization form. (Inherited from Encoding)
IsAlwaysNormalized(NormalizationForm)	When overridden in a derived class, gets a value indicating whether the current encoding is always normalized, using the specified normalization form. (Inherited from Encoding)
MemberwiseClone()	Creates a shallow copy of the current Object. (Inherited from Object)
ToString()	Returns a string that represents the current object. (Inherited from Object)
TryGetBytes(ReadOnlySpan<Char>, Span<Byte>, Int32)	Encodes into a span of bytes a set of characters from the specified read-only span if the destination is large enough. (Inherited from Encoding)
TryGetChars(ReadOnlySpan<Byte>, Span<Char>, Int32)	Decodes into a span of chars a set of bytes from the specified read-only span if the destination is large enough. (Inherited from Encoding)

Extension Methods

GetBytes(Encoding, ReadOnlySequence<Char>, IBufferWriter<Byte>)	Decodes the specified ReadOnlySequence<T> to bytes using the specified Encoding and writes the result to writer.
GetBytes(Encoding, ReadOnlySequence<Char>, Span<Byte>)	Encodes the specified ReadOnlySequence<T> to bytes using the specified Encoding and outputs the result to bytes.
GetBytes(Encoding, ReadOnlySequence<Char>)	Encodes the specified ReadOnlySequence<T> into a Byte array using the specified Encoding.
GetBytes(Encoding, ReadOnlySpan<Char>, IBufferWriter<Byte>)	Encodes the specified ReadOnlySpan<T> to bytes using the specified Encoding and writes the result to writer.
GetChars(Encoding, ReadOnlySequence<Byte>, IBufferWriter<Char>)	Decodes the specified ReadOnlySequence<T> to chars using the specified Encoding and writes the result to writer.
GetChars(Encoding, ReadOnlySequence<Byte>, Span<Char>)	Decodes the specified ReadOnlySequence<T> to chars using the specified Encoding and outputs the result to chars.
GetChars(Encoding, ReadOnlySpan<Byte>, IBufferWriter<Char>)	Decodes the specified ReadOnlySpan<T> to chars using the specified Encoding and writes the result to writer.
GetString(Encoding, ReadOnlySequence<Byte>)	Decodes the specified ReadOnlySequence<T> into a String using the specified Encoding.

See also

• Decoder
• Encoder
• Understanding Encodings