Udostępnij za pośrednictwem


Encoding.BigEndianUnicode Właściwość

Definicja

Pobiera kodowanie dla formatu UTF-16, który używa kolejności bajtów big endian.

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

Wartość właściwości

Obiekt kodowania dla formatu UTF-16, który używa kolejności bajtów big endian.

Przykłady

Poniższy przykład odczytuje plik tekstowy z kodowaniem UTF-16 przy użyciu kolejności bajtów big endian.

using namespace System;
using namespace System::IO;
int main()
{
   
   // Read a text file saved with Big Endian Unicode encoding.
   System::Text::Encoding^ encoding = System::Text::Encoding::BigEndianUnicode;
   StreamReader^ reader = gcnew StreamReader( "TextFile.txt",encoding );
   String^ line = reader->ReadLine();
   while ( line != nullptr )
   {
      Console::WriteLine( line );
      line = reader->ReadLine();
   }
}
using System;
using System.IO;

namespace BigEndianExample
{
   public class Class1 
   {
      public static void Main(string[] args) 
      {
         // Read a text file saved with Big Endian Unicode encoding.
         System.Text.Encoding encoding = System.Text.Encoding.BigEndianUnicode;
         StreamReader reader = new StreamReader("TextFile.txt", encoding);
         string line = reader.ReadLine();
         while (line != null) 
         {
            Console.WriteLine(line);
            line = reader.ReadLine();
         }
       }
    }
}
Imports System.IO

Namespace BigEndianExample
   Public Class Class1
      Public Overloads Shared Sub Main()
         ' Read a text file saved with Big Endian Unicode encoding.
         Dim encoding As System.Text.Encoding = System.Text.Encoding.BigEndianUnicode
         Dim reader As New StreamReader("TextFile.txt", encoding)
         Dim line As String = reader.ReadLine()
         While Not (line Is Nothing)
            Console.WriteLine(line)
            line = reader.ReadLine()
         End While
      End Sub
   End Class
End Namespace

Poniższy przykład określa liczbę bajtów wymaganych do zakodowania tablicy znaków, koduje znaki i wyświetla wynikowe bajty.

using namespace System;
using namespace System::Text;
void PrintCountsAndBytes( array<Char>^chars, Encoding^ enc );
void PrintHexBytes( array<Byte>^bytes );
int main()
{
   
   // The characters to encode:
   //    Latin Small Letter Z (U+007A)
   //    Latin Small Letter A (U+0061)
   //    Combining Breve (U+0306)
   //    Latin Small Letter AE With Acute (U+01FD)
   //    Greek Small Letter Beta (U+03B2)
   //    a high-surrogate value (U+D8FF)
   //    a low-surrogate value (U+DCFF)
   array<Char>^myChars = gcnew array<Char>{
      L'z','a',L'\u0306',L'\u01FD',L'\u03B2',L'\xD8FF',L'\xDCFF'
   };
   
   // Get different encodings.
   Encoding^ u7 = Encoding::UTF7;
   Encoding^ u8 = Encoding::UTF8;
   Encoding^ u16LE = Encoding::Unicode;
   Encoding^ u16BE = Encoding::BigEndianUnicode;
   Encoding^ u32 = Encoding::UTF32;
   
   // Encode the entire array, and print out the counts and the resulting bytes.
   PrintCountsAndBytes( myChars, u7 );
   PrintCountsAndBytes( myChars, u8 );
   PrintCountsAndBytes( myChars, u16LE );
   PrintCountsAndBytes( myChars, u16BE );
   PrintCountsAndBytes( myChars, u32 );
}

void PrintCountsAndBytes( array<Char>^chars, Encoding^ enc )
{
   
   // Display the name of the encoding used.
   Console::Write( "{0,-30} :", enc );
   
   // Display the exact byte count.
   int iBC = enc->GetByteCount( chars );
   Console::Write( " {0,-3}", iBC );
   
   // Display the maximum byte count.
   int iMBC = enc->GetMaxByteCount( chars->Length );
   Console::Write( " {0,-3} :", iMBC );
   
   // Encode the array of chars.
   array<Byte>^bytes = enc->GetBytes( chars );
   
   // Display all the encoded bytes.
   PrintHexBytes( bytes );
}

void PrintHexBytes( array<Byte>^bytes )
{
   if ( (bytes == nullptr) || (bytes->Length == 0) )
      Console::WriteLine( "<none>" );
   else
   {
      for ( int i = 0; i < bytes->Length; i++ )
         Console::Write( "{0:X2} ", bytes[ i ] );
      Console::WriteLine();
   }
}

/* 
This code produces the following output.

System.Text.UTF7Encoding       : 18  23  :7A 61 2B 41 77 59 42 2F 51 4F 79 32 50 2F 63 2F 77 2D
System.Text.UTF8Encoding       : 12  24  :7A 61 CC 86 C7 BD CE B2 F1 8F B3 BF
System.Text.UnicodeEncoding    : 14  16  :7A 00 61 00 06 03 FD 01 B2 03 FF D8 FF DC
System.Text.UnicodeEncoding    : 14  16  :00 7A 00 61 03 06 01 FD 03 B2 D8 FF DC FF
System.Text.UTF32Encoding      : 24  32  :7A 00 00 00 61 00 00 00 06 03 00 00 FD 01 00 00 B2 03 00 00 FF FC 04 00

*/
using System;
using System.Text;

public class SamplesEncoding  {

   public static void Main()  {

      // The characters to encode:
      //    Latin Small Letter Z (U+007A)
      //    Latin Small Letter A (U+0061)
      //    Combining Breve (U+0306)
      //    Latin Small Letter AE With Acute (U+01FD)
      //    Greek Small Letter Beta (U+03B2)
      //    a high-surrogate value (U+D8FF)
      //    a low-surrogate value (U+DCFF)
      char[] myChars = new char[] { 'z', 'a', '\u0306', '\u01FD', '\u03B2', '\uD8FF', '\uDCFF' };

      // Get different encodings.
      Encoding  u7    = Encoding.UTF7;
      Encoding  u8    = Encoding.UTF8;
      Encoding  u16LE = Encoding.Unicode;
      Encoding  u16BE = Encoding.BigEndianUnicode;
      Encoding  u32   = Encoding.UTF32;

      // Encode the entire array, and print out the counts and the resulting bytes.
      PrintCountsAndBytes( myChars, u7 );
      PrintCountsAndBytes( myChars, u8 );
      PrintCountsAndBytes( myChars, u16LE );
      PrintCountsAndBytes( myChars, u16BE );
      PrintCountsAndBytes( myChars, u32 );
   }

   public static void PrintCountsAndBytes( char[] chars, Encoding enc )  {

      // Display the name of the encoding used.
      Console.Write( "{0,-30} :", enc.ToString() );

      // Display the exact byte count.
      int iBC  = enc.GetByteCount( chars );
      Console.Write( " {0,-3}", iBC );

      // Display the maximum byte count.
      int iMBC = enc.GetMaxByteCount( chars.Length );
      Console.Write( " {0,-3} :", iMBC );

      // Encode the array of chars.
      byte[] bytes = enc.GetBytes( chars );

      // Display all the encoded bytes.
      PrintHexBytes( bytes );
   }

   public static void PrintHexBytes( byte[] bytes )  {

      if (( bytes == null ) || ( bytes.Length == 0 ))
        {
            Console.WriteLine( "<none>" );
        }
        else  {
         for ( int i = 0; i < bytes.Length; i++ )
            Console.Write( "{0:X2} ", bytes[i] );
         Console.WriteLine();
      }
   }
}


/* 
This code produces the following output.

System.Text.UTF7Encoding       : 18  23  :7A 61 2B 41 77 59 42 2F 51 4F 79 32 50 2F 63 2F 77 2D
System.Text.UTF8Encoding       : 12  24  :7A 61 CC 86 C7 BD CE B2 F1 8F B3 BF
System.Text.UnicodeEncoding    : 14  16  :7A 00 61 00 06 03 FD 01 B2 03 FF D8 FF DC
System.Text.UnicodeEncoding    : 14  16  :00 7A 00 61 03 06 01 FD 03 B2 D8 FF DC FF
System.Text.UTF32Encoding      : 24  32  :7A 00 00 00 61 00 00 00 06 03 00 00 FD 01 00 00 B2 03 00 00 FF FC 04 00

*/
Imports System.Text

Public Class SamplesEncoding   

   Public Shared Sub Main()

      ' The characters to encode:
      '    Latin Small Letter Z (U+007A)
      '    Latin Small Letter A (U+0061)
      '    Combining Breve (U+0306)
      '    Latin Small Letter AE With Acute (U+01FD)
      '    Greek Small Letter Beta (U+03B2)
      '    a high-surrogate value (U+D8FF)
      '    a low-surrogate value (U+DCFF)
      Dim myChars() As Char = {"z"c, "a"c, ChrW(&H0306), ChrW(&H01FD), ChrW(&H03B2), ChrW(&HD8FF), ChrW(&HDCFF)}
 

      ' Get different encodings.
      Dim u7 As Encoding = Encoding.UTF7
      Dim u8 As Encoding = Encoding.UTF8
      Dim u16LE As Encoding = Encoding.Unicode
      Dim u16BE As Encoding = Encoding.BigEndianUnicode
      Dim u32 As Encoding = Encoding.UTF32

      ' Encode the entire array, and print out the counts and the resulting bytes.
      PrintCountsAndBytes(myChars, u7)
      PrintCountsAndBytes(myChars, u8)
      PrintCountsAndBytes(myChars, u16LE)
      PrintCountsAndBytes(myChars, u16BE)
      PrintCountsAndBytes(myChars, u32)

   End Sub


   Public Shared Sub PrintCountsAndBytes(chars() As Char, enc As Encoding)

      ' Display the name of the encoding used.
      Console.Write("{0,-30} :", enc.ToString())

      ' Display the exact byte count.
      Dim iBC As Integer = enc.GetByteCount(chars)
      Console.Write(" {0,-3}", iBC)

      ' Display the maximum byte count.
      Dim iMBC As Integer = enc.GetMaxByteCount(chars.Length)
      Console.Write(" {0,-3} :", iMBC)

      ' Encode the array of chars.
      Dim bytes As Byte() = enc.GetBytes(chars)

      ' Display all the encoded bytes.
      PrintHexBytes(bytes)

   End Sub


   Public Shared Sub PrintHexBytes(bytes() As Byte)

      If bytes Is Nothing OrElse bytes.Length = 0 Then
         Console.WriteLine("<none>")
      Else
         Dim i As Integer
         For i = 0 To bytes.Length - 1
            Console.Write("{0:X2} ", bytes(i))
         Next i
         Console.WriteLine()
      End If

   End Sub

End Class


'This code produces the following output.
'
'System.Text.UTF7Encoding       : 18  23  :7A 61 2B 41 77 59 42 2F 51 4F 79 32 50 2F 63 2F 77 2D
'System.Text.UTF8Encoding       : 12  24  :7A 61 CC 86 C7 BD CE B2 F1 8F B3 BF
'System.Text.UnicodeEncoding    : 14  16  :7A 00 61 00 06 03 FD 01 B2 03 FF D8 FF DC
'System.Text.UnicodeEncoding    : 14  16  :00 7A 00 61 03 06 01 FD 03 B2 D8 FF DC FF
'System.Text.UTF32Encoding      : 24  32  :7A 00 00 00 61 00 00 00 06 03 00 00 FD 01 00 00 B2 03 00 00 FF FC 04 00

Uwagi

Obiekt UnicodeEncoding zwrócony przez tę właściwość może nie mieć odpowiedniego zachowania dla aplikacji. Używa rezerwowego zamiany, aby zastąpić każdy ciąg, którego nie może zakodować i każdy bajt, którego nie może dekodować znakiem zapytania ("?"). Zamiast tego można wywołać konstruktor w UnicodeEncoding.UnicodeEncoding(Boolean, Boolean, Boolean) celu utworzenia wystąpienia obiektu big endian UnicodeEncoding , którego rezerwowanie jest elementem EncoderFallbackException lub , DecoderFallbackExceptionjak pokazano w poniższym przykładzie.

using System;
using System.Text;

public class Example
{
   public static void Main()
   {
      byte[] bytes = { 0x00, 0x20, 0xd8, 0x01, 0x00, 0x68, 0xA7, 0x00 };
      Encoding enc = new UnicodeEncoding(true, true, true);
      
      try {
         string value = enc.GetString(bytes);
         Console.WriteLine();
         Console.WriteLine("'{0}'", value);
      }
      catch (DecoderFallbackException e) {      
         Console.WriteLine("Unable to decode {0} at index {1}", 
                           ShowBytes(e.BytesUnknown), e.Index);
      }
   }

   private static string ShowBytes(byte[] bytes) 
   {
      string returnString = null;
      foreach (var byteValue in bytes)
         returnString += String.Format("0x{0:X2} ", byteValue);

      return returnString.Trim();
   }
}
// The example displays the following output:
//        Unable to decode 0xD8 0x01 at index 4
Imports System.Text

Module Example
   Public Sub Main()
      Dim bytes() As Byte = { &h00, &h20, &hd8, &h01, &h00, &h68, &hA7, &h00}
      Dim enc As Encoding = New UnicodeEncoding(True, True, True)
      
      Try
         Dim value As String = enc.GetString(bytes)
         Console.WriteLine()
         Console.WriteLine("'{0}'", value)
      Catch e As DecoderFallbackException      
         Console.WriteLine("Unable to decode {0} at index {1}", 
                           ShowBytes(e.BytesUnknown), e.Index)
      End Try
   End Sub
   
   Private Function ShowBytes(bytes As Byte()) As String
      Dim returnString As String = Nothing
      For Each byteValue In bytes
         returnString += String.Format("0x{0:X2} ", byteValue)
      Next
      Return returnString.Trim()
   End Function
End Module
' The example displays the following output:
'       Unable to decode 0xD8 0x01 at index 4

Zwrócony UnicodeEncoding obiekt ma BodyNamewłaściwości , HeaderNamei WebName , które dają nazwę "unicodeFFFE". Chociaż znak kolejności bajtów big endian jest szesnastkowy FEFF, nazwa "unicodeFFFE" została wybrana, ponieważ znak kolejności bajtów jest wyświetlany jako szesnastkowy FFFE na małych komputerach z systemem Windows endian.

Dotyczy

Zobacz też