UnicodeEncoding Costruttori

public:
 UnicodeEncoding();

public UnicodeEncoding ();

Public Sub New ()

Esempio

Nell'esempio seguente viene illustrato come creare una nuova UnicodeEncoding istanza e visualizzare il nome della codifica.

using namespace System;
using namespace System::Text;
int main()
{
   UnicodeEncoding^ unicode = gcnew UnicodeEncoding;
   String^ encodingName = unicode->EncodingName;
   Console::WriteLine( "Encoding name: {0}", encodingName );
}

using System;
using System.Text;

class UnicodeEncodingExample {
    public static void Main() {
        UnicodeEncoding unicode = new UnicodeEncoding();
        String encodingName = unicode.EncodingName;
        Console.WriteLine("Encoding name: " + encodingName);
    }
}

Imports System.Text

Class UnicodeEncodingExample

    Public Shared Sub Main()
        Dim uni As New UnicodeEncoding()
        Dim encodingName As String = uni.EncodingName
        Console.WriteLine("Encoding name: " & encodingName)
    End Sub
End Class

Commenti

Questo costruttore crea un'istanza che usa l'ordine di byte endian piccolo, fornisce un contrassegno di ordine di byte Unicode e non genera un'eccezione quando viene rilevata una codifica non valida.

public:
 UnicodeEncoding(bool bigEndian, bool byteOrderMark);

public UnicodeEncoding (bool bigEndian, bool byteOrderMark);

new System.Text.UnicodeEncoding : bool * bool -> System.Text.UnicodeEncoding

Public Sub New (bigEndian As Boolean, byteOrderMark As Boolean)

Parametri

Esempio

Nell'esempio seguente viene illustrato come creare una nuova UnicodeEncoding istanza specificando se supportare l'ordinamento di byte endian o big endian little endian e il contrassegno di ordine di byte Unicode.

using namespace System;
using namespace System::Text;
void DescribeEquivalence( Boolean isEquivalent )
{
   Console::WriteLine( " {0} equivalent encoding.", (isEquivalent ? (String^)"An" : "Not an") );
}

int main()
{
   
   // Create a UnicodeEncoding without parameters.
   UnicodeEncoding^ unicode = gcnew UnicodeEncoding;
   
   // Create a UnicodeEncoding to support little-endian Byte ordering
   // and include the Unicode Byte order mark.
   UnicodeEncoding^ unicodeLittleEndianBOM = gcnew UnicodeEncoding( false,true );
   
   // Compare this UnicodeEncoding to the UnicodeEncoding without parameters.
   DescribeEquivalence( unicode->Equals( unicodeLittleEndianBOM ) );
   
   // Create a UnicodeEncoding to support little-endian Byte ordering
   // and not include the Unicode Byte order mark.
   UnicodeEncoding^ unicodeLittleEndianNoBOM = gcnew UnicodeEncoding( false,false );
   
   // Compare this UnicodeEncoding to the UnicodeEncoding without parameters.
   DescribeEquivalence( unicode->Equals( unicodeLittleEndianNoBOM ) );
   
   // Create a UnicodeEncoding to support big-endian Byte ordering
   // and include the Unicode Byte order mark.
   UnicodeEncoding^ unicodeBigEndianBOM = gcnew UnicodeEncoding( true,true );
   
   // Compare this UnicodeEncoding to the UnicodeEncoding without parameters.
   DescribeEquivalence( unicode->Equals( unicodeBigEndianBOM ) );
   
   // Create a UnicodeEncoding to support big-endian Byte ordering
   // and not include the Unicode Byte order mark.
   UnicodeEncoding^ unicodeBigEndianNoBOM = gcnew UnicodeEncoding( true,false );
   
   // Compare this UnicodeEncoding to the UnicodeEncoding without parameters.
   DescribeEquivalence( unicode->Equals( unicodeBigEndianNoBOM ) );
}

using System;
using System.Text;

class UnicodeEncodingExample {
    public static void Main() {

        // Create a UnicodeEncoding without parameters.
        UnicodeEncoding unicode = new UnicodeEncoding();

        // Create a UnicodeEncoding to support little-endian byte ordering
        // and include the Unicode byte order mark.
        UnicodeEncoding unicodeLittleEndianBOM = 
            new UnicodeEncoding(false, true);
        // Compare this UnicodeEncoding to the UnicodeEncoding without parameters.
        DescribeEquivalence(unicode.Equals(unicodeLittleEndianBOM));

        // Create a UnicodeEncoding to support little-endian byte ordering
        // and not include the Unicode byte order mark.
        UnicodeEncoding unicodeLittleEndianNoBOM =
            new UnicodeEncoding(false, false);
        // Compare this UnicodeEncoding to the UnicodeEncoding without parameters.
        DescribeEquivalence(unicode.Equals(unicodeLittleEndianNoBOM));

        // Create a UnicodeEncoding to support big-endian byte ordering
        // and include the Unicode byte order mark.
        UnicodeEncoding unicodeBigEndianBOM =
            new UnicodeEncoding(true, true);
        // Compare this UnicodeEncoding to the UnicodeEncoding without parameters.
        DescribeEquivalence(unicode.Equals(unicodeBigEndianBOM));

        // Create a UnicodeEncoding to support big-endian byte ordering
        // and not include the Unicode byte order mark.
        UnicodeEncoding unicodeBigEndianNoBOM =
            new UnicodeEncoding(true, false);
        // Compare this UnicodeEncoding to the UnicodeEncoding without parameters.
        DescribeEquivalence(unicode.Equals(unicodeBigEndianNoBOM));
    }

    public static void DescribeEquivalence(Boolean isEquivalent) {
        Console.WriteLine(
            "{0} equivalent encoding.", (isEquivalent ? "An" : "Not an")
        );
    }
}

Imports System.Text

Class UnicodeEncodingExample
    
    Public Shared Sub Main()

        ' Create a UnicodeEncoding without parameters.
        Dim unicodeDefault As New UnicodeEncoding()

        ' Create a UnicodeEncoding to support little-endian byte ordering
        ' and include the Unicode byte order mark.        
        Dim unicodeLittleEndianBOM As New UnicodeEncoding(False, True)
        ' Compare this UnicodeEncoding to the UnicodeEncoding without parameters.
        DescribeEquivalence(unicodeDefault.Equals(unicodeLittleEndianBOM))
        
        ' Create a UnicodeEncoding to support little-endian byte ordering
        ' and not include the Unicode byte order mark.
        Dim unicodeLittleEndianNoBOM As New UnicodeEncoding(False, False)
        ' Compare this UnicodeEncoding to the UnicodeEncoding without parameters.
        DescribeEquivalence(unicodeDefault.Equals(unicodeLittleEndianNoBOM))
        
        ' Create a UnicodeEncoding to support big-endian byte ordering
        ' and include the Unicode byte order mark.
        Dim unicodeBigEndianBOM As New UnicodeEncoding(True, True)
        ' Compare this UnicodeEncoding to the UnicodeEncoding without parameters.
        DescribeEquivalence(unicodeDefault.Equals(unicodeBigEndianBOM))
        
        ' Create a UnicodeEncoding to support big-endian byte ordering
        ' and not include the Unicode byte order mark.
        Dim unicodeBigEndianNoBOM As New UnicodeEncoding(True, False)
        ' Compare this UnicodeEncoding to the UnicodeEncoding without parameters.
        DescribeEquivalence(unicodeDefault.Equals(unicodeBigEndianNoBOM))
    End Sub
    
    
    Public Shared Sub DescribeEquivalence(isEquivalent As Boolean)
        Dim phrase as String
        If isEquivalent Then
            phrase = "An"
        Else
            phrase = "Not an"
        End If
        Console.WriteLine("{0} equivalent encoding.", phrase)
    End Sub
End Class

Commenti

Questo costruttore crea un'istanza che non genera un'eccezione quando viene rilevata una codifica non valida.

Il byteOrderMark parametro controlla l'operazione del GetPreamble metodo. Se true, il metodo restituisce una matrice di byte contenente il contrassegno dell'ordine di byte Unicode (BOM) in formato UTF-16. Se false, restituisce una matrice di byte a lunghezza zero. Tuttavia, l'impostazione byteOrderMark su true non comporta che il GetBytes metodo prefissi la BOM all'inizio della matrice di byte, né che il GetByteCount metodo includa il numero di byte nel conteggio dei byte.

Vedi anche

• GetPreamble()

public:
 UnicodeEncoding(bool bigEndian, bool byteOrderMark, bool throwOnInvalidBytes);

public UnicodeEncoding (bool bigEndian, bool byteOrderMark, bool throwOnInvalidBytes);

new System.Text.UnicodeEncoding : bool * bool * bool -> System.Text.UnicodeEncoding

Public Sub New (bigEndian As Boolean, byteOrderMark As Boolean, throwOnInvalidBytes As Boolean)

Parametri

Esempio

Nell'esempio seguente viene illustrato il comportamento di UnicodeEncoding, sia con il rilevamento degli errori abilitato che senza.

using namespace System;
using namespace System::Text;
void PrintDecodedString( array<Byte>^bytes, Encoding^ enc );
int main()
{
   
   // Create an instance of UnicodeEncoding using little-endian byte order.
   // This will be used for encoding.
   UnicodeEncoding^ u16LE = gcnew UnicodeEncoding( false,true );
   
   // Create two instances of UnicodeEncoding using big-endian byte order: one with error detection and one without.
   // These will be used for decoding.
   UnicodeEncoding^ u16withED = gcnew UnicodeEncoding( true,true,true );
   UnicodeEncoding^ u16noED = gcnew UnicodeEncoding( true,true,false );
   
   // Create byte arrays from the same string containing the following characters:
   //    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)
   //    Latin Capital Letter U with  Diaeresis (U+00DC)
   String^ myStr = "za\u0306\u01FD\u03B2\u00DC";
   
   // Encode the string using little-endian byte order.
   array<Byte>^myBytes = gcnew array<Byte>(u16LE->GetByteCount( myStr ));
   u16LE->GetBytes( myStr, 0, myStr->Length, myBytes, 0 );
   
   // Decode the byte array with error detection.
   Console::WriteLine( "Decoding with error detection:" );
   PrintDecodedString( myBytes, u16withED );
   
   // Decode the byte array without error detection.
   Console::WriteLine( "Decoding without error detection:" );
   PrintDecodedString( myBytes, u16noED );
}


// Decode the bytes and display the string.
void PrintDecodedString( array<Byte>^bytes, Encoding^ enc )
{
   try
   {
      Console::WriteLine( "   Decoded string: {0}", enc->GetString( bytes, 0, bytes->Length ) );
   }
   catch ( System::ArgumentException^ e ) 
   {
      Console::WriteLine( e );
   }

   Console::WriteLine();
}

using System;
using System.Text;

public class SamplesUnicodeEncoding  {

   public static void Main()  {

      // Create an instance of UnicodeEncoding using little-endian byte order.
      // This will be used for encoding.
      UnicodeEncoding u16LE     = new UnicodeEncoding( false, true );

      // Create two instances of UnicodeEncoding using big-endian byte order: one with error detection and one without.
      // These will be used for decoding.
      UnicodeEncoding u16withED = new UnicodeEncoding( true, true, true );
      UnicodeEncoding u16noED   = new UnicodeEncoding( true, true, false );

      // Create byte arrays from the same string containing the following characters:
      //    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)
      //    Latin Capital Letter U with  Diaeresis (U+00DC)
      String myStr = "za\u0306\u01FD\u03B2\u00DC";

      // Encode the string using little-endian byte order.
      byte[] myBytes = new byte[u16LE.GetByteCount( myStr )];
      u16LE.GetBytes( myStr, 0, myStr.Length, myBytes, 0 );

      // Decode the byte array with error detection.
      Console.WriteLine( "Decoding with error detection:" );
      PrintDecodedString( myBytes, u16withED );

      // Decode the byte array without error detection.
      Console.WriteLine( "Decoding without error detection:" );
      PrintDecodedString( myBytes, u16noED );
   }

   // Decode the bytes and display the string.
   public static void PrintDecodedString( byte[] bytes, Encoding enc )  {

      try  {
         Console.WriteLine( "   Decoded string: {0}", enc.GetString( bytes, 0, bytes.Length ) );
      }
      catch ( System.ArgumentException e )  {
         Console.WriteLine( e.ToString() );
      }

      Console.WriteLine();
   }
}

Imports System.Text

Public Class SamplesUnicodeEncoding   

   Public Shared Sub Main()

      ' Create an instance of UnicodeEncoding using little-endian byte order.
      ' This will be used for encoding.
      Dim u16LE As New UnicodeEncoding(False, True)

      ' Create two instances of UnicodeEncoding using big-endian byte order: one with error detection and one without.
      ' These will be used for decoding.
      Dim u16withED As New UnicodeEncoding(True, True, True)
      Dim u16noED As New UnicodeEncoding(True, True, False)

      ' Create byte arrays from the same string containing the following characters:
      '    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)
      '    Latin Capital Letter U with  Diaeresis (U+00DC)
      Dim myStr As String = "za" & ChrW(&H0306) & ChrW(&H01FD) & ChrW(&H03B2) & ChrW(&H00DC)

      ' Encode the string using little-endian byte order.
      Dim myBytes(u16LE.GetByteCount(myStr)) As Byte
      u16LE.GetBytes(myStr, 0, myStr.Length, myBytes, 0)

      ' Decode the byte array with error detection.
      Console.WriteLine("Decoding with error detection:")
      PrintDecodedString(myBytes, u16withED)

      ' Decode the byte array without error detection.
      Console.WriteLine("Decoding without error detection:")
      PrintDecodedString(myBytes, u16noED)

   End Sub


   ' Decode the bytes and display the string.
   Public Shared Sub PrintDecodedString(bytes() As Byte, enc As Encoding)

      Try
         Console.WriteLine("   Decoded string: {0}", enc.GetString(bytes, 0, bytes.Length))
      Catch e As System.ArgumentException
         Console.WriteLine(e.ToString())
      End Try

      Console.WriteLine()

   End Sub

End Class

Commenti

Il byteOrderMark parametro controlla l'operazione del GetPreamble metodo. Se true, il metodo restituisce una matrice di byte contenente il contrassegno dell'ordine di byte Unicode (BOM) in formato UTF-16. Se false, restituisce una matrice di byte a lunghezza zero. Tuttavia, l'impostazione byteOrderMark su true non comporta che il GetBytes metodo prefissi la BOM all'inizio della matrice di byte, né che il GetByteCount metodo includa il numero di byte nel conteggio dei byte.

Se il throwOnInvalidBytes parametro è true, un metodo che rileva una sequenza di byte non valida genera System.ArgumentException. In caso contrario, il metodo non genera un'eccezione e la sequenza non valida viene ignorata.

Vedi anche

• GetPreamble()