Encoding.GetByteCount Encoding.GetByteCount Encoding.GetByteCount Encoding.GetByteCount Method

Definición

Cuando se reemplaza en una clase derivada, calcula el número de bytes que se generan al codificar un juego de caracteres.When overridden in a derived class, calculates the number of bytes produced by encoding a set of characters.

Sobrecargas

GetByteCount(String, Int32, Int32) GetByteCount(String, Int32, Int32) GetByteCount(String, Int32, Int32) GetByteCount(String, Int32, Int32)
GetByteCount(Char[], Int32, Int32) GetByteCount(Char[], Int32, Int32) GetByteCount(Char[], Int32, Int32) GetByteCount(Char[], Int32, Int32)

Cuando se reemplaza en una clase derivada, calcula el número de bytes que se generan al codificar un juego de caracteres de la matriz de caracteres especificada.When overridden in a derived class, calculates the number of bytes produced by encoding a set of characters from the specified character array.

GetByteCount(Char*, Int32) GetByteCount(Char*, Int32) GetByteCount(Char*, Int32)

Cuando se reemplaza en una clase derivada, calcula el número de bytes que se generan al codificar un juego de caracteres a partir del puntero de caracteres especificado.When overridden in a derived class, calculates the number of bytes produced by encoding a set of characters starting at the specified character pointer.

GetByteCount(String) GetByteCount(String) GetByteCount(String) GetByteCount(String)

Cuando se reemplaza en una clase derivada, calcula el número de bytes que se generan al codificar los caracteres de la cadena especificada.When overridden in a derived class, calculates the number of bytes produced by encoding the characters in the specified string.

GetByteCount(ReadOnlySpan<Char>) GetByteCount(ReadOnlySpan<Char>) GetByteCount(ReadOnlySpan<Char>) GetByteCount(ReadOnlySpan<Char>)
GetByteCount(Char[]) GetByteCount(Char[]) GetByteCount(Char[]) GetByteCount(Char[])

Cuando se reemplaza en una clase derivada, calcula el número de bytes que se generan al codificar todos los caracteres de la matriz de caracteres especificada.When overridden in a derived class, calculates the number of bytes produced by encoding all the characters in the specified character array.

GetByteCount(String, Int32, Int32) GetByteCount(String, Int32, Int32) GetByteCount(String, Int32, Int32) GetByteCount(String, Int32, Int32)

public:
 int GetByteCount(System::String ^ s, int index, int count);
public int GetByteCount (string s, int index, int count);
member this.GetByteCount : string * int * int -> int
Public Function GetByteCount (s As String, index As Integer, count As Integer) As Integer

Parámetros

Devoluciones

GetByteCount(Char[], Int32, Int32) GetByteCount(Char[], Int32, Int32) GetByteCount(Char[], Int32, Int32) GetByteCount(Char[], Int32, Int32)

Cuando se reemplaza en una clase derivada, calcula el número de bytes que se generan al codificar un juego de caracteres de la matriz de caracteres especificada.When overridden in a derived class, calculates the number of bytes produced by encoding a set of characters from the specified character array.

public:
 abstract int GetByteCount(cli::array <char> ^ chars, int index, int count);
public abstract int GetByteCount (char[] chars, int index, int count);
abstract member GetByteCount : char[] * int * int -> int
Public MustOverride Function GetByteCount (chars As Char(), index As Integer, count As Integer) As Integer

Parámetros

chars
Char[]

Matriz de caracteres que contiene el juego de caracteres que se va a codificar.The character array containing the set of characters to encode.

index
Int32 Int32 Int32 Int32

Índice del primer carácter que se va a codificar.The index of the first character to encode.

count
Int32 Int32 Int32 Int32

Número de caracteres que se van a codificar.The number of characters to encode.

Devoluciones

Número de bytes que se generan al codificar los caracteres especificados.The number of bytes produced by encoding the specified characters.

Excepciones

index o count es menor que cero.index or count is less than zero.

O bien-or- index y count no denotan un intervalo válido en chars.index and count do not denote a valid range in chars.

Se ha producido una acción de reserva (vea Codificación de caracteres de .NET para obtener una explicación completa)A fallback occurred (see Character Encoding in .NET for complete explanation) - y --and- El valor de EncoderFallback está establecido en EncoderExceptionFallback.EncoderFallback is set to EncoderExceptionFallback.

Ejemplos

El ejemplo siguiente determina el número de bytes necesarios para codificar tres caracteres de una matriz de caracteres, codifica los caracteres y muestra los bytes resultantes.The following example determines the number of bytes required to encode three characters from a character array, encodes the characters, and displays the resulting bytes.

using namespace System;
using namespace System::Text;
void PrintCountsAndBytes( array<Char>^chars, int index, int count, 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',L'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 three characters starting at index 4, and print out the counts and the resulting bytes.
   PrintCountsAndBytes( myChars, 4, 3, u7 );
   PrintCountsAndBytes( myChars, 4, 3, u8 );
   PrintCountsAndBytes( myChars, 4, 3, u16LE );
   PrintCountsAndBytes( myChars, 4, 3, u16BE );
   PrintCountsAndBytes( myChars, 4, 3, u32 );
}

void PrintCountsAndBytes( array<Char>^chars, int index, int count, Encoding^ enc )
{
   
   // Display the name of the encoding used.
   Console::Write( "{0,-30} :", enc );
   
   // Display the exact byte count.
   int iBC = enc->GetByteCount( chars, index, count );
   Console::Write( " {0,-3}", iBC );
   
   // Display the maximum byte count.
   int iMBC = enc->GetMaxByteCount( count );
   Console::Write( " {0,-3} :", iMBC );
   
   // Encode the array of chars.
   array<Byte>^bytes = enc->GetBytes( chars, index, count );
   
   // The following is an alternative way to encode the array of chars:
   // byte[] bytes = new byte[iBC];
   // enc.GetBytes( chars, index, count, bytes, bytes.GetLowerBound(0) );
   // 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       : 10  11  :2B 41 37 4C 59 2F 39 7A 2F 2D
System.Text.UTF8Encoding       : 6   12  :CE B2 F1 8F B3 BF
System.Text.UnicodeEncoding    : 6   8   :B2 03 FF D8 FF DC
System.Text.UnicodeEncoding    : 6   8   :03 B2 D8 FF DC FF
System.Text.UTF32Encoding      : 8   16  :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 three characters starting at index 4, and print out the counts and the resulting bytes.
      PrintCountsAndBytes( myChars, 4, 3, u7 );
      PrintCountsAndBytes( myChars, 4, 3, u8 );
      PrintCountsAndBytes( myChars, 4, 3, u16LE );
      PrintCountsAndBytes( myChars, 4, 3, u16BE );
      PrintCountsAndBytes( myChars, 4, 3, u32 );

   }


   public static void PrintCountsAndBytes( char[] chars, int index, int count, 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, index, count );
      Console.Write( " {0,-3}", iBC );

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

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

      // The following is an alternative way to encode the array of chars:
      // byte[] bytes = new byte[iBC];
      // enc.GetBytes( chars, index, count, bytes, bytes.GetLowerBound(0) );

      // 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       : 10  11  :2B 41 37 4C 59 2F 39 7A 2F 2D
System.Text.UTF8Encoding       : 6   12  :CE B2 F1 8F B3 BF
System.Text.UnicodeEncoding    : 6   8   :B2 03 FF D8 FF DC
System.Text.UnicodeEncoding    : 6   8   :03 B2 D8 FF DC FF
System.Text.UTF32Encoding      : 8   16  :B2 03 00 00 FF FC 04 00

*/

Imports System
Imports System.Text
Imports Microsoft.VisualBasic

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 three characters starting at index 4, and print out the counts and the resulting bytes.
      PrintCountsAndBytes(myChars, 4, 3, u7)
      PrintCountsAndBytes(myChars, 4, 3, u8)
      PrintCountsAndBytes(myChars, 4, 3, u16LE)
      PrintCountsAndBytes(myChars, 4, 3, u16BE)
      PrintCountsAndBytes(myChars, 4, 3, u32)

   End Sub 'Main


   Public Shared Sub PrintCountsAndBytes(chars() As Char, index As Integer, count As Integer, 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, index, count)
      Console.Write(" {0,-3}", iBC)

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

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

      ' The following is an alternative way to encode the array of chars:
      ' NOTE: In VB.NET, arrays contain one extra element by default.
      '       The following line creates the array with the exact number of elements required.
      ' Dim bytes(iBC - 1) As Byte
      ' enc.GetBytes( chars, index, count, bytes, bytes.GetLowerBound(0) )

      ' Display all the encoded bytes.
      PrintHexBytes(bytes)

   End Sub 'PrintCountsAndBytes


   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 'PrintHexBytes 

End Class 'SamplesEncoding


'This code produces the following output.
'
'System.Text.UTF7Encoding       : 10  11  :2B 41 37 4C 59 2F 39 7A 2F 2D
'System.Text.UTF8Encoding       : 6   12  :CE B2 F1 8F B3 BF
'System.Text.UnicodeEncoding    : 6   8   :B2 03 FF D8 FF DC
'System.Text.UnicodeEncoding    : 6   8   :03 B2 D8 FF DC FF
'System.Text.UTF32Encoding      : 8   16  :B2 03 00 00 FF FC 04 00

Comentarios

Para calcular el tamaño exacto de matriz requerido GetBytes para almacenar los bytes resultantes, llame a la GetByteCount método.To calculate the exact array size required by GetBytes to store the resulting bytes, call the GetByteCount method. Para calcular el tamaño máximo de la matriz, llame a la GetMaxByteCount método.To calculate the maximum array size, call the GetMaxByteCount method. El GetByteCount método generalmente permite asignar menos memoria, mientras que el GetMaxByteCount método generalmente se ejecuta con mayor rapidez.The GetByteCount method generally allows allocation of less memory, while the GetMaxByteCount method generally executes faster.

El GetByteCount método determina el número de bytes resultante de codificar un juego de caracteres Unicode y el GetBytes método realiza la codificación real.The GetByteCount method determines how many bytes result in encoding a set of Unicode characters, and the GetBytes method performs the actual encoding. El GetBytes método espera conversiones discretas, en contraposición al Encoder.GetBytes método, que administra varias conversiones en un único flujo de entrada.The GetBytes method expects discrete conversions, in contrast to the Encoder.GetBytes method, which handles multiple conversions on a single input stream.

Varias versiones de GetByteCount y GetBytes son compatibles.Several versions of GetByteCount and GetBytes are supported. Éstas son algunas consideraciones de programación para su uso de estos métodos:The following are some programming considerations for use of these methods:

  • Para codificar los caracteres de entrada muchas a una página de códigos y procesar los caracteres utilizando varias llamadas, podría necesitar la aplicación.Your app might need to encode many input characters to a code page and process the characters using multiple calls. En este caso, probablemente necesite mantener el estado entre llamadas, teniendo en cuenta el estado que se conserve el Encoder de objeto que se va a usar.In this case, you probably need to maintain state between calls, taking into account the state that is persisted by the Encoder object being used.

  • Si la aplicación controla las entradas de cadena, la versión de cadena GetBytes se recomienda.If your app handles string inputs, the string version of GetBytes is recommended.

  • La versión del búfer de caracteres Unicode de GetBytes(Char*, Int32, Byte*, Int32) permite algunas técnicas rápidas, especialmente con varias llamadas mediante la Encoder objeto o insertar en los búferes existentes.The Unicode character buffer version of GetBytes(Char*, Int32, Byte*, Int32) allows some fast techniques, particularly with multiple calls using the Encoder object or inserting into existing buffers. Tenga en cuenta, sin embargo, esta versión del método a veces es segura, puesto que los punteros son necesarios.Bear in mind, however, that this method version is sometimes unsafe, since pointers are required.

  • Si la aplicación debe convertir una gran cantidad de datos, debe volver a usar el búfer de salida.If your app must convert a large amount of data, it should reuse the output buffer. En este caso, el GetBytes versión que admita las matrices de bytes es la mejor opción.In this case, the GetBytes version that supports byte arrays is the best choice.

  • Considere el uso de la Encoder.Convert método en lugar de GetByteCount.Consider using the Encoder.Convert method instead of GetByteCount. El método de conversión convierte tantos datos como sea posible y producir una excepción si el búfer de salida es demasiado pequeño.The conversion method converts as much data as possible, and does throw an exception if the output buffer is too small. Para la codificación continua de un flujo, este método suele ser la mejor opción.For continuous encoding of a stream, this method is often the best choice.

Consulte también:

GetByteCount(Char*, Int32) GetByteCount(Char*, Int32) GetByteCount(Char*, Int32)

Importante

Esta API no es conforme a CLS.

Cuando se reemplaza en una clase derivada, calcula el número de bytes que se generan al codificar un juego de caracteres a partir del puntero de caracteres especificado.When overridden in a derived class, calculates the number of bytes produced by encoding a set of characters starting at the specified character pointer.

public:
 virtual int GetByteCount(char* chars, int count);
[System.CLSCompliant(false)]
[System.Runtime.InteropServices.ComVisible(false)]
[System.Security.SecurityCritical]
public virtual int GetByteCount (char* chars, int count);
abstract member GetByteCount : nativeptr<char> * int -> int
override this.GetByteCount : nativeptr<char> * int -> int

Parámetros

chars
Char*

Puntero al primer carácter que se va a codificar.A pointer to the first character to encode.

count
Int32 Int32 Int32 Int32

Número de caracteres que se van a codificar.The number of characters to encode.

Devoluciones

Número de bytes que se generan al codificar los caracteres especificados.The number of bytes produced by encoding the specified characters.

Excepciones

Se ha producido una acción de reserva (vea Codificación de caracteres de .NET para obtener una explicación completa)A fallback occurred (see Character Encoding in .NET for complete explanation) - y --and- El valor de EncoderFallback está establecido en EncoderExceptionFallback.EncoderFallback is set to EncoderExceptionFallback.

Comentarios

La matriz exacta para calcular el tamaño que GetBytes requiere para almacenar los bytes resultantes, debe llamar a la GetByteCount método.To calculate the exact array size that GetBytes requires to store the resulting bytes, you should call the GetByteCount method. Para calcular el tamaño máximo de la matriz, llame a la GetMaxByteCount método.To calculate the maximum array size, call the GetMaxByteCount method. El GetByteCount método generalmente permite asignar menos memoria, mientras que el GetMaxByteCount método generalmente se ejecuta con mayor rapidez.The GetByteCount method generally allows allocation of less memory, while the GetMaxByteCount method generally executes faster.

El GetByteCount(Char*, Int32) método determina el número de bytes resultante de codificar un juego de caracteres Unicode y el GetBytes(Char*, Int32, Byte*, Int32) método realiza la codificación real.The GetByteCount(Char*, Int32) method determines how many bytes result in encoding a set of Unicode characters, and the GetBytes(Char*, Int32, Byte*, Int32) method performs the actual encoding. El GetBytes método espera conversiones discretas, en contraposición al Encoder.GetBytes método, que administra varias conversiones en un único flujo de entrada.The GetBytes method expects discrete conversions, in contrast to the Encoder.GetBytes method, which handles multiple conversions on a single input stream.

Varias versiones de GetByteCount y GetBytes son compatibles.Several versions of GetByteCount and GetBytes are supported. Éstas son algunas consideraciones sobre el uso de estos métodos:The following are some considerations for using these methods:

  • Puede necesitar la aplicación codificar los caracteres de entrada muchas a una página de códigos y procesar los caracteres utilizando varias llamadas.Your app may need to encode many input characters to a code page and process the characters using multiple calls. En este caso, probablemente necesite mantener el estado entre llamadas, teniendo en cuenta el estado que se conserve el Encoder de objeto que se va a usar.In this case, you probably need to maintain state between calls, taking into account the state that is persisted by the Encoder object being used.

  • Si la aplicación controla las entradas de cadena, debe usar la versión de cadena del GetBytes método.If your app handles string inputs, you should use the string version of the GetBytes method.

  • La versión del búfer de caracteres Unicode de GetBytes permite algunas técnicas rápidas, especialmente con varias llamadas mediante la Encoder objeto o insertar en los búferes existentes.The Unicode character buffer version of GetBytes allows some fast techniques, particularly with multiple calls using the Encoder object or inserting into existing buffers. Tenga en cuenta, sin embargo, esta versión del método a veces es segura, puesto que los punteros son necesarios.Bear in mind, however, that this method version is sometimes unsafe, since pointers are required.

  • Si la aplicación debe convertir una gran cantidad de datos, debe volver a usar el búfer de salida.If your app must convert a large amount of data, it should reuse the output buffer. En este caso, el GetBytes versión que admita las matrices de bytes es la mejor opción.In this case, the GetBytes version that supports byte arrays is the best choice.

  • Considere el uso de la Encoder.Convert método en lugar de GetByteCount.Consider using the Encoder.Convert method instead of GetByteCount. El método de conversión convierte tantos datos como sea posible y producir una excepción si el búfer de salida es demasiado pequeño.The conversion method converts as much data as possible, and does throw an exception if the output buffer is too small. Para la codificación continua de un flujo, este método suele ser la mejor opción.For continuous encoding of a stream, this method is often the best choice.

Seguridad

SecurityCriticalAttribute
requiere plena confianza para el llamador inmediato.Requires full trust for the immediate caller. Este miembro no se puede usar código de confianza parcial o transparente.This member cannot be used by partially trusted or transparent code.

Consulte también:

GetByteCount(String) GetByteCount(String) GetByteCount(String) GetByteCount(String)

Cuando se reemplaza en una clase derivada, calcula el número de bytes que se generan al codificar los caracteres de la cadena especificada.When overridden in a derived class, calculates the number of bytes produced by encoding the characters in the specified string.

public:
 virtual int GetByteCount(System::String ^ s);
public virtual int GetByteCount (string s);
abstract member GetByteCount : string -> int
override this.GetByteCount : string -> int
Public Overridable Function GetByteCount (s As String) As Integer

Parámetros

s
String String String String

Cadena que contiene el juego de caracteres que se va a codificar.The string containing the set of characters to encode.

Devoluciones

Número de bytes que se generan al codificar los caracteres especificados.The number of bytes produced by encoding the specified characters.

Excepciones

Se ha producido una acción de reserva (vea Codificación de caracteres de .NET para obtener una explicación completa)A fallback occurred (see Character Encoding in .NET for complete explanation) - y --and- El valor de EncoderFallback está establecido en EncoderExceptionFallback.EncoderFallback is set to EncoderExceptionFallback.

Ejemplos

El ejemplo siguiente determina el número de bytes necesarios para codificar una cadena o un rango en la cadena, codifica los caracteres y muestra los bytes resultantes.The following example determines the number of bytes required to encode a string or a range in the string, encodes the characters, and displays the resulting bytes.

using namespace System;
using namespace System::Text;
void PrintCountsAndBytes( String^ s, Encoding^ enc );
void PrintCountsAndBytes( String^ s, int index, int count, 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)
   String^ myStr = L"za\u0306\u01FD\u03B2\xD8FF\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 string, and print out the counts and the resulting bytes.
   Console::WriteLine( "Encoding the entire string:" );
   PrintCountsAndBytes( myStr, u7 );
   PrintCountsAndBytes( myStr, u8 );
   PrintCountsAndBytes( myStr, u16LE );
   PrintCountsAndBytes( myStr, u16BE );
   PrintCountsAndBytes( myStr, u32 );
   Console::WriteLine();
   
   // Encode three characters starting at index 4, and print out the counts and the resulting bytes.
   Console::WriteLine( "Encoding the characters from index 4 through 6:" );
   PrintCountsAndBytes( myStr, 4, 3, u7 );
   PrintCountsAndBytes( myStr, 4, 3, u8 );
   PrintCountsAndBytes( myStr, 4, 3, u16LE );
   PrintCountsAndBytes( myStr, 4, 3, u16BE );
   PrintCountsAndBytes( myStr, 4, 3, u32 );
}

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

void PrintCountsAndBytes( String^ s, int index, int count, Encoding^ enc )
{
   
   // Display the name of the encoding used.
   Console::Write( "{0,-30} :", enc );
   
   // Display the exact byte count.
   int iBC = enc->GetByteCount( s->ToCharArray(), index, count );
   Console::Write( " {0,-3}", iBC );
   
   // Display the maximum byte count.
   int iMBC = enc->GetMaxByteCount( count );
   Console::Write( " {0,-3} :", iMBC );
   
   // Encode a range of characters in the string.
   array<Byte>^bytes = gcnew array<Byte>(iBC);
   enc->GetBytes( s, index, count, bytes, bytes->GetLowerBound( 0 ) );
   
   // 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.

Encoding the entire string:
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

Encoding the characters from index 4 through 6:
System.Text.UTF7Encoding       : 10  11  :2B 41 37 4C 59 2F 39 7A 2F 2D
System.Text.UTF8Encoding       : 6   12  :CE B2 F1 8F B3 BF
System.Text.UnicodeEncoding    : 6   8   :B2 03 FF D8 FF DC
System.Text.UnicodeEncoding    : 6   8   :03 B2 D8 FF DC FF
System.Text.UTF32Encoding      : 8   16  :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)
      String myStr = "za\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 string, and print out the counts and the resulting bytes.
      Console.WriteLine( "Encoding the entire string:" );
      PrintCountsAndBytes( myStr, u7 );
      PrintCountsAndBytes( myStr, u8 );
      PrintCountsAndBytes( myStr, u16LE );
      PrintCountsAndBytes( myStr, u16BE );
      PrintCountsAndBytes( myStr, u32 );

      Console.WriteLine();

      // Encode three characters starting at index 4, and print out the counts and the resulting bytes.
      Console.WriteLine( "Encoding the characters from index 4 through 6:" );
      PrintCountsAndBytes( myStr, 4, 3, u7 );
      PrintCountsAndBytes( myStr, 4, 3, u8 );
      PrintCountsAndBytes( myStr, 4, 3, u16LE );
      PrintCountsAndBytes( myStr, 4, 3, u16BE );
      PrintCountsAndBytes( myStr, 4, 3, u32 );

   }


   public static void PrintCountsAndBytes( String s, Encoding enc )  {

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

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

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

      // Encode the entire string.
      byte[] bytes = enc.GetBytes( s );

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

   }


   public static void PrintCountsAndBytes( String s, int index, int count, Encoding enc )  {

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

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

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

      // Encode a range of characters in the string.
      byte[] bytes = new byte[iBC];
      enc.GetBytes( s, index, count, bytes, bytes.GetLowerBound(0) );

      // 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.

Encoding the entire string:
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

Encoding the characters from index 4 through 6:
System.Text.UTF7Encoding       : 10  11  :2B 41 37 4C 59 2F 39 7A 2F 2D
System.Text.UTF8Encoding       : 6   12  :CE B2 F1 8F B3 BF
System.Text.UnicodeEncoding    : 6   8   :B2 03 FF D8 FF DC
System.Text.UnicodeEncoding    : 6   8   :03 B2 D8 FF DC FF
System.Text.UTF32Encoding      : 8   16  :B2 03 00 00 FF FC 04 00

*/

Imports System
Imports System.Text
Imports Microsoft.VisualBasic

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 myStr As String = "za" & 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 string, and print out the counts and the resulting bytes.
      Console.WriteLine("Encoding the entire string:")
      PrintCountsAndBytes(myStr, u7)
      PrintCountsAndBytes(myStr, u8)
      PrintCountsAndBytes(myStr, u16LE)
      PrintCountsAndBytes(myStr, u16BE)
      PrintCountsAndBytes(myStr, u32)

      Console.WriteLine()

      ' Encode three characters starting at index 4, and print out the counts and the resulting bytes.
      Console.WriteLine("Encoding the characters from index 4 through 6:")
      PrintCountsAndBytes(myStr, 4, 3, u7)
      PrintCountsAndBytes(myStr, 4, 3, u8)
      PrintCountsAndBytes(myStr, 4, 3, u16LE)
      PrintCountsAndBytes(myStr, 4, 3, u16BE)
      PrintCountsAndBytes(myStr, 4, 3, u32)

   End Sub 'Main


   Overloads Public Shared Sub PrintCountsAndBytes(s As String, 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(s)
      Console.Write(" {0,-3}", iBC)

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

      ' Encode the entire string.
      Dim bytes As Byte() = enc.GetBytes(s)

      ' Display all the encoded bytes.
      PrintHexBytes(bytes)

   End Sub 'PrintCountsAndBytes


   Overloads Public Shared Sub PrintCountsAndBytes(s As String, index As Integer, count As Integer, 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(s.ToCharArray(), index, count)
      Console.Write(" {0,-3}", iBC)

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

      ' Encode a range of characters in the string.
      ' NOTE: In VB.NET, arrays contain one extra element by default.
      '       The following line creates the array with the exact number of elements required.
      Dim bytes(iBC - 1) As Byte
      enc.GetBytes(s, index, count, bytes, bytes.GetLowerBound(0))

      ' Display all the encoded bytes.
      PrintHexBytes(bytes)

   End Sub 'PrintCountsAndBytes


   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 'PrintHexBytes 

End Class 'SamplesEncoding


'This code produces the following output.
'
'Encoding the entire string:
'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
'
'Encoding the characters from index 4 through 6:
'System.Text.UTF7Encoding       : 10  11  :2B 41 37 4C 59 2F 39 7A 2F 2D
'System.Text.UTF8Encoding       : 6   12  :CE B2 F1 8F B3 BF
'System.Text.UnicodeEncoding    : 6   8   :B2 03 FF D8 FF DC
'System.Text.UnicodeEncoding    : 6   8   :03 B2 D8 FF DC FF
'System.Text.UTF32Encoding      : 8   16  :B2 03 00 00 FF FC 04 00

Comentarios

Para calcular el tamaño exacto de matriz requerido GetBytes para almacenar los bytes resultantes, llame a la GetByteCount método.To calculate the exact array size required by GetBytes to store the resulting bytes, call the GetByteCount method. Para calcular el tamaño máximo de la matriz, llame a la GetMaxByteCount método.To calculate the maximum array size, call the GetMaxByteCount method. El GetByteCount método generalmente permite asignar menos memoria, mientras que el GetMaxByteCount método generalmente se ejecuta con mayor rapidez.The GetByteCount method generally allows allocation of less memory, while the GetMaxByteCount method generally executes faster.

El GetByteCount método determina el número de bytes resultante de codificar un juego de caracteres Unicode y el GetBytes método realiza la codificación real.The GetByteCount method determines how many bytes result in encoding a set of Unicode characters, and the GetBytes method performs the actual encoding. El GetBytes método espera conversiones discretas, en contraposición al Encoder.GetBytes método, que administra varias conversiones en un único flujo de entrada.The GetBytes method expects discrete conversions, in contrast to the Encoder.GetBytes method, which handles multiple conversions on a single input stream.

Varias versiones de GetByteCount y GetBytes son compatibles.Several versions of GetByteCount and GetBytes are supported. Éstas son algunas consideraciones de programación para su uso de estos métodos:The following are some programming considerations for use of these methods:

  • Para codificar los caracteres de entrada muchas a una página de códigos y procesar los caracteres utilizando varias llamadas, podría necesitar la aplicación.Your app might need to encode many input characters to a code page and process the characters using multiple calls. En este caso, probablemente necesite mantener el estado entre llamadas, teniendo en cuenta el estado que se conserve el Encoder de objeto que se va a usar.In this case, you probably need to maintain state between calls, taking into account the state that is persisted by the Encoder object being used.

  • Si la aplicación controla las entradas de cadena, la versión de cadena GetBytes se recomienda.If your app handles string inputs, the string version of GetBytes is recommended.

  • La versión del búfer de caracteres Unicode de GetBytes(Char*, Int32, Byte*, Int32) permite algunas técnicas rápidas, especialmente con varias llamadas mediante la Encoder objeto o insertar en los búferes existentes.The Unicode character buffer version of GetBytes(Char*, Int32, Byte*, Int32) allows some fast techniques, particularly with multiple calls using the Encoder object or inserting into existing buffers. Tenga en cuenta, sin embargo, esta versión del método a veces es segura, puesto que los punteros son necesarios.Bear in mind, however, that this method version is sometimes unsafe, since pointers are required.

  • Si la aplicación debe convertir una gran cantidad de datos, debe volver a usar el búfer de salida.If your app must convert a large amount of data, it should reuse the output buffer. En este caso, el GetBytes versión que admita las matrices de bytes es la mejor opción.In this case, the GetBytes version that supports byte arrays is the best choice.

  • Considere el uso de la Encoder.Convert método en lugar de GetByteCount.Consider using the Encoder.Convert method instead of GetByteCount. El método de conversión convierte tantos datos como sea posible y producir una excepción si el búfer de salida es demasiado pequeño.The conversion method converts as much data as possible, and does throw an exception if the output buffer is too small. Para la codificación continua de un flujo, este método suele ser la mejor opción.For continuous encoding of a stream, this method is often the best choice.

Consulte también:

GetByteCount(ReadOnlySpan<Char>) GetByteCount(ReadOnlySpan<Char>) GetByteCount(ReadOnlySpan<Char>) GetByteCount(ReadOnlySpan<Char>)

public:
 virtual int GetByteCount(ReadOnlySpan<char> chars);
public virtual int GetByteCount (ReadOnlySpan<char> chars);
abstract member GetByteCount : ReadOnlySpan<char> -> int
override this.GetByteCount : ReadOnlySpan<char> -> int
Public Overridable Function GetByteCount (chars As ReadOnlySpan(Of Char)) As Integer

Parámetros

Devoluciones

GetByteCount(Char[]) GetByteCount(Char[]) GetByteCount(Char[]) GetByteCount(Char[])

Cuando se reemplaza en una clase derivada, calcula el número de bytes que se generan al codificar todos los caracteres de la matriz de caracteres especificada.When overridden in a derived class, calculates the number of bytes produced by encoding all the characters in the specified character array.

public:
 virtual int GetByteCount(cli::array <char> ^ chars);
public virtual int GetByteCount (char[] chars);
abstract member GetByteCount : char[] -> int
override this.GetByteCount : char[] -> int
Public Overridable Function GetByteCount (chars As Char()) As Integer

Parámetros

chars
Char[]

Matriz de caracteres que contiene los caracteres que se codifican.The character array containing the characters to encode.

Devoluciones

Número de bytes generados al codificar todos los caracteres de la matriz de caracteres especificada.The number of bytes produced by encoding all the characters in the specified character array.

Excepciones

Se ha producido una acción de reserva (vea Codificación de caracteres de .NET para obtener una explicación completa)A fallback occurred (see Character Encoding in .NET for complete explanation) - y --and- El valor de EncoderFallback está establecido en EncoderExceptionFallback.EncoderFallback is set to EncoderExceptionFallback.

Ejemplos

El ejemplo siguiente determina el número de bytes necesarios para codificar una matriz de caracteres, codifica los caracteres y muestra los bytes resultantes.The following example determines the number of bytes required to encode a character array, encodes the characters, and displays the resulting bytes.

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
Imports System.Text
Imports Microsoft.VisualBasic

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 'Main


   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 'PrintCountsAndBytes


   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 'PrintHexBytes 

End Class 'SamplesEncoding


'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

Comentarios

Para calcular el tamaño exacto de matriz requerido GetBytes para almacenar los bytes resultantes, llame a la GetByteCount método.To calculate the exact array size required by GetBytes to store the resulting bytes, call the GetByteCount method. Para calcular el tamaño máximo de la matriz, llame a la GetMaxByteCount método.To calculate the maximum array size, call the GetMaxByteCount method. El GetByteCount método generalmente permite asignar menos memoria, mientras que el GetMaxByteCount método generalmente se ejecuta con mayor rapidez.The GetByteCount method generally allows allocation of less memory, while the GetMaxByteCount method generally executes faster.

El GetByteCount método determina el número de bytes resultante de codificar un juego de caracteres Unicode y el GetBytes método realiza la codificación real.The GetByteCount method determines how many bytes result in encoding a set of Unicode characters, and the GetBytes method performs the actual encoding. El GetBytes método espera conversiones discretas, en contraposición al Encoder.GetBytes método, que administra varias conversiones en un único flujo de entrada.The GetBytes method expects discrete conversions, in contrast to the Encoder.GetBytes method, which handles multiple conversions on a single input stream.

Varias versiones de GetByteCount y GetBytes son compatibles.Several versions of GetByteCount and GetBytes are supported. Éstas son algunas consideraciones de programación para su uso de estos métodos:The following are some programming considerations for use of these methods:

  • Para codificar los caracteres de entrada muchas a una página de códigos y procesar los caracteres utilizando varias llamadas, podría necesitar la aplicación.Your app might need to encode many input characters to a code page and process the characters using multiple calls. En este caso, probablemente necesite mantener el estado entre llamadas, teniendo en cuenta el estado que se conserve el Encoder de objeto que se va a usar.In this case, you probably need to maintain state between calls, taking into account the state that is persisted by the Encoder object being used.

  • Si la aplicación controla las entradas de cadena, debe usar las versiones de cadena de la GetBytes método.If your app handles string inputs, you should use the string versions of the GetBytes method.

  • La versión del búfer de caracteres Unicode de GetBytes(Char*, Int32, Byte*, Int32) permite algunas técnicas rápidas, especialmente con varias llamadas mediante la Encoder objeto o insertar en los búferes existentes.The Unicode character buffer version of GetBytes(Char*, Int32, Byte*, Int32) allows some fast techniques, particularly with multiple calls using the Encoder object or inserting into existing buffers. Tenga en cuenta, sin embargo, esta versión del método a veces es segura, puesto que los punteros son necesarios.Bear in mind, however, that this method version is sometimes unsafe, since pointers are required.

  • Si la aplicación debe convertir una gran cantidad de datos, debe volver a usar el búfer de salida.If your app must convert a large amount of data, you should reuse the output buffer. En este caso, el GetBytes versión que admita las matrices de bytes es la mejor opción.In this case, the GetBytes version that supports byte arrays is the best choice.

  • Considere el uso de la Encoder.Convert método en lugar de GetByteCount.Consider using the Encoder.Convert method instead of GetByteCount. El método de conversión convierte tantos datos como sea posible y producir una excepción si el búfer de salida es demasiado pequeño.The conversion method converts as much data as possible, and does throw an exception if the output buffer is too small. Para la codificación continua de un flujo, este método suele ser la mejor opción.For continuous encoding of a stream, this method is often the best choice.

Consulte también:

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