Encoding.UTF8 Encoding.UTF8 Encoding.UTF8 Encoding.UTF8 Property

Définition

Obtient un encodage pour le format UTF-8.Gets an encoding for the UTF-8 format.

public:
 static property System::Text::Encoding ^ UTF8 { System::Text::Encoding ^ get(); };
public static System.Text.Encoding UTF8 { get; }
member this.UTF8 : System.Text.Encoding
Public Shared ReadOnly Property UTF8 As Encoding

Valeur de propriété

Encodage pour le format UTF-8.An encoding for the UTF-8 format.

Exemples

L’exemple suivant définit un tableau composé des caractères suivants :The following example defines an array that consists of the following characters:

  • LETTRE MINUSCULE LATINE Z (U + 007A)LATIN SMALL LETTER Z (U+007A)

  • LETTRE MINUSCULE LATINE A (U + 0061)LATIN SMALL LETTER A (U+0061)

  • DIACRITIQUE BRÈVE (U + 0306)COMBINING BREVE (U+0306)

  • LETTRE MINUSCULE LATINE AE AVEC ACCENT AIGU (U + 01FD)LATIN SMALL LETTER AE WITH ACUTE (U+01FD)

  • LETTRE MINUSCULE GRECQUE BÊTA (U + 03B2)GREEK SMALL LETTER BETA (U+03B2)

  • Paire de substitution (U + D800 U + DD54) qui forme les États ACROPHONIC grec ATTIC 1000 (U + 10154).A surrogate pair (U+D800 U+DD54) that forms GREEK ACROPHONIC ATTIC ONE THOUSAND STATERS (U+10154).

Il affiche les unités de code UTF-16 de chaque caractère et détermine le nombre d’octets requis par un encodeur UTF-8 pour encoder le tableau de caractères.It displays the UTF-16 code units of each character and determines the number of bytes required by a UTF-8 encoder to encode the character array. Il encode ensuite les caractères et affiche les octets encodés en UTF-8 résultants.It then encodes the characters and displays the resulting UTF-8-encoded bytes.

using System;
using System.Text;

public class Example
{
   public static void Main()  
   {
      // Create a character array.
      string gkNumber = Char.ConvertFromUtf32(0x10154);
      char[] chars = new char[] { 'z', 'a', '\u0306', '\u01FD', '\u03B2', 
                                  gkNumber[0], gkNumber[1] };

      // Get UTF-8 and UTF-16 encoders.
      Encoding utf8 = Encoding.UTF8;
      Encoding utf16 = Encoding.Unicode;
      
      // Display the original characters' code units.
      Console.WriteLine("Original UTF-16 code units:");
      byte[] utf16Bytes = utf16.GetBytes(chars);
      foreach (var utf16Byte in utf16Bytes)
         Console.Write("{0:X2} ", utf16Byte);
      Console.WriteLine();
         
      // Display the number of bytes required to encode the array.
      int reqBytes  = utf8.GetByteCount(chars);
      Console.WriteLine("\nExact number of bytes required: {0}", 
                    reqBytes);

      // Display the maximum byte count.
      int maxBytes = utf8.GetMaxByteCount(chars.Length);
      Console.WriteLine("Maximum number of bytes required: {0}\n", 
                        maxBytes);

      // Encode the array of chars.
      byte[] utf8Bytes = utf8.GetBytes(chars);

      // Display all the UTF-8-encoded bytes.
      Console.WriteLine("UTF-8-encoded code units:");
      foreach (var utf8Byte in utf8Bytes)
         Console.Write("{0:X2} ", utf8Byte);
      Console.WriteLine();
   }
}
// The example displays the following output:
//       Original UTF-16 code units:
//       7A 00 61 00 06 03 FD 01 B2 03 00 D8 54 DD
//       
//       Exact number of bytes required: 12
//       Maximum number of bytes required: 24
//       
//       UTF-8-encoded code units:
//       7A 61 CC 86 C7 BD CE B2 F0 90 85 94
Imports System.Text

Public Module Example
   Public Sub Main()
      ' Create a character array.
      Dim gkNumber As String = Char.ConvertFromUtf32(&h10154)
      Dim chars() As Char = {"z"c, "a"c, ChrW(&H0306), ChrW(&H01FD), 
                             ChrW(&H03B2), gkNumber(0), gkNumber(1) }
 
      ' Get UTF-8 and UTF-16 encoders.
      Dim utf8 As Encoding = Encoding.UTF8
      Dim utf16 As Encoding = Encoding.Unicode

      ' Display the original characters' code units.
      Console.WriteLine("Original UTF-16 code units:")
      Dim utf16Bytes() As Byte = utf16.GetBytes(chars)
      For Each utf16Byte In utf16Bytes
         Console.Write("{0:X2} ", utf16Byte)
      Next
      Console.WriteLine()

      Console.WriteLine()
      ' Display the number of bytes required to encode the array.
      Dim reqBytes As Integer = utf8.GetByteCount(chars)
      Console.WriteLine("Exact number of bytes required: {0}", 
                        reqBytes)

      ' Display the maximum byte count.
      Dim maxBytes As Integer = utf8.GetMaxByteCount(chars.Length)
      Console.WriteLine("Maximum number of bytes required: {0}", 
                        maxBytes)
      Console.WriteLine()
      
      ' Encode the array of characters.
      Dim utf8Bytes() As Byte = utf8.GetBytes(chars)

      ' Display all the UTF-8-encoded bytes.
      Console.WriteLine("UTF-8-encoded code units:")
      For Each utf8Byte In utf8Bytes
         Console.Write("{0:X2} ", utf8Byte)
      Next
      Console.WriteLine()
   End Sub 
End Module 
' The example displays the following output:
'    Original UTF-16 code units:
'    7A 00 61 00 06 03 FD 01 B2 03 00 D8 54 DD
'    
'    Exact number of bytes required: 12
'    Maximum number of bytes required: 24
'    
'    UTF-8-encoded code units:
'    7A 61 CC 86 C7 BD CE B2 F0 90 85 94

Remarques

Cette propriété retourne un UTF8Encoding objet qui encode les caractères Unicode (encodés UTF-16) en une séquence de un à quatre octets par caractère, et qui décode un tableau d’octets encodé en UTF-8 en caractères Unicode (encodés UTF-16).This property returns a UTF8Encoding object that encodes Unicode (UTF-16-encoded) characters into a sequence of one to four bytes per character, and that decodes a UTF-8-encoded byte array to Unicode (UTF-16-encoded) characters. Pour plus d’informations sur les encodages de caractères pris en charge par .NET et sur l’encodage Unicode à utiliser, consultez encodage de caractères dans .net.For information about the character encodings supported by .NET and a discussion of which Unicode encoding to use, see Character Encoding in .NET.

L' UTF8Encoding objet retourné par cette propriété peut ne pas avoir le comportement approprié pour votre application.The UTF8Encoding object that is returned by this property might not have the appropriate behavior for your app.

  • Elle retourne un UTF8Encoding objet qui fournit une marque d’ordre d’octet (BOM) Unicode.It returns a UTF8Encoding object that provides a Unicode byte order mark (BOM). Pour instancier un encodage UTF8 qui ne fournit pas de nomenclature, appelez une UTF8Encoding surcharge du constructeur.To instantiate a UTF8 encoding that doesn't provide a BOM, call any overload of the UTF8Encoding constructor.

  • Elle retourne un UTF8Encoding objet qui utilise le secours de remplacement pour remplacer chaque chaîne qu’il ne peut pas encoder et chaque octet qu’il ne peut pas décoder par un point d’interrogation («  ? »).It returns a UTF8Encoding object that uses replacement fallback to replace each string that it can't encode and each byte that it can't decode with a question mark ("?") character. Au lieu de cela, vous UTF8Encoding.UTF8Encoding(Boolean, Boolean) pouvez appeler le constructeur UTF8Encoding pour instancier un objet EncoderFallbackException dont la valeur DecoderFallbackExceptionde secours est ou, comme l’illustre l’exemple suivant.Instead, you can call the UTF8Encoding.UTF8Encoding(Boolean, Boolean) constructor to instantiate a UTF8Encoding object whose fallback is either an EncoderFallbackException or a DecoderFallbackException, as the following example illustrates.

    using System;
    using System.Text;
    
    public class Example
    {
       public static void Main()
       {
          Encoding enc = new UTF8Encoding(true, true);
          string value = "\u00C4 \uD802\u0033 \u00AE"; 
    
          try {
             byte[] bytes= enc.GetBytes(value);
             foreach (var byt in bytes)
                Console.Write("{0:X2} ", byt);
             Console.WriteLine();
    
             string value2 = enc.GetString(bytes);
             Console.WriteLine(value2);
          }
          catch (EncoderFallbackException e) {
             Console.WriteLine("Unable to encode {0} at index {1}", 
                               e.IsUnknownSurrogate() ? 
                                  String.Format("U+{0:X4} U+{1:X4}", 
                                                Convert.ToUInt16(e.CharUnknownHigh),
                                                Convert.ToUInt16(e.CharUnknownLow)) :
                                  String.Format("U+{0:X4}", 
                                                Convert.ToUInt16(e.CharUnknown)),
                               e.Index);
          }                     
       }
    }
    // The example displays the following output:
    //        Unable to encode U+D802 at index 2
    
    Imports System.Text
    
    Module Example
       Public Sub Main()
          Dim enc As Encoding = New UTF8Encoding(True, True)
          Dim value As String = String.Format("{0} {1}{2} {3}", 
                                ChrW(&h00C4), ChrW(&hD802), ChrW(&h0033), ChrW(&h00AE))
          
          Try
             Dim bytes() As Byte = enc.GetBytes(value)
             For Each byt As Byte In bytes
                Console.Write("{0:X2} ", byt)
             Next       
             Console.WriteLine()
             Dim value2 As String = enc.GetString(bytes)
             Console.WriteLine(value2)
          Catch e As EncoderFallbackException
             Console.WriteLine("Unable to encode {0} at index {1}", 
                               If(e.IsUnknownSurrogate(), 
                                  String.Format("U+{0:X4} U+{1:X4}", 
                                                Convert.ToUInt16(e.CharUnknownHigh),
                                                Convert.ToUInt16(e.CharUnknownLow)),
                                  String.Format("U+{0:X4}", 
                                                Convert.ToUInt16(e.CharUnknown))),
                               e.Index)
          End Try
       End Sub
    End Module
    ' The example displays the following output:
    '       Unable to encode U+D802 at index 2
    

S’applique à

Voir aussi