Encoding.GetChars 方法

定义

在派生类中重写时,将一个字节序列解码为一组字符。When overridden in a derived class, decodes a sequence of bytes into a set of characters.

重载

GetChars(Byte[], Int32, Int32, Char[], Int32)

在派生类中重写时,将指定字节数组中的字节序列解码为指定的字符数组。When overridden in a derived class, decodes a sequence of bytes from the specified byte array into the specified character array.

GetChars(Byte*, Int32, Char*, Int32)

在派生类中重写时,将一个字节序列(从指定的字节指针开始)解码为一组字符,并从指定的字符指针开始存储该组字符。When overridden in a derived class, decodes a sequence of bytes starting at the specified byte pointer into a set of characters that are stored starting at the specified character pointer.

GetChars(ReadOnlySpan<Byte>, Span<Char>)

在派生类中重写时,将指定只读字节范围中的所有字节解码为字符范围。When overridden in a derived class, decodes all the bytes in the specified read-only byte span into a character span.

GetChars(Byte[], Int32, Int32)

在派生类中重写时,将指定字节数组中的一个字节序列解码为一组字符。When overridden in a derived class, decodes a sequence of bytes from the specified byte array into a set of characters.

GetChars(Byte[])

在派生类中重写时,将指定字节数组中的所有字节解码为一组字符。When overridden in a derived class, decodes all the bytes in the specified byte array into a set of characters.

GetChars(Byte[], Int32, Int32, Char[], Int32)

在派生类中重写时,将指定字节数组中的字节序列解码为指定的字符数组。When overridden in a derived class, decodes a sequence of bytes from the specified byte array into the specified character array.

public:
 abstract int GetChars(cli::array <System::Byte> ^ bytes, int byteIndex, int byteCount, cli::array <char> ^ chars, int charIndex);
public abstract int GetChars (byte[] bytes, int byteIndex, int byteCount, char[] chars, int charIndex);
abstract member GetChars : byte[] * int * int * char[] * int -> int
Public MustOverride Function GetChars (bytes As Byte(), byteIndex As Integer, byteCount As Integer, chars As Char(), charIndex As Integer) As Integer

参数

bytes
Byte[]

包含要解码的字节序列的字节数组。The byte array containing the sequence of bytes to decode.

byteIndex
Int32

第一个要解码的字节的索引。The index of the first byte to decode.

byteCount
Int32

要解码的字节数。The number of bytes to decode.

chars
Char[]

要用于包含所产生的字符集的字符数组。The character array to contain the resulting set of characters.

charIndex
Int32

开始写入所产生的字符集的索引位置。The index at which to start writing the resulting set of characters.

返回

Int32

写入 chars 的实际字符数。The actual number of characters written into chars.

例外

bytesnullbytes is null.

-or-

charsnullchars is null.

byteIndexbyteCountcharIndex 小于零。byteIndex or byteCount or charIndex is less than zero.

-or-

byteindexbyteCount 不表示 bytes中的有效范围。byteindex and byteCount do not denote a valid range in bytes.

-or-

charIndex 不是 chars 中的有效索引。charIndex is not a valid index in chars.

chars 中从 charIndex 到数组结尾没有足够容量来容纳所产生的字符。chars does not have enough capacity from charIndex to the end of the array to accommodate the resulting characters.

发生回退(有关详细信息,请参阅采用 .NET 的字符编码A fallback occurred (for more information, see Character Encoding in .NET)

-和--and-

DecoderFallback 设置为 DecoderExceptionFallbackDecoderFallback is set to DecoderExceptionFallback.

示例

下面的示例将字符串从一种编码转换为另一种编码。The following example converts a string from one encoding to another.

using namespace System;
using namespace System::Text;

int main()
{
   String^ unicodeString = "This string contains the unicode character Pi (\u03a0)";
   
   // Create two different encodings.
   Encoding^ ascii = Encoding::ASCII;
   Encoding^ unicode = Encoding::Unicode;
   
   // Convert the string into a byte array.
   array<Byte>^unicodeBytes = unicode->GetBytes( unicodeString );
   
   // Perform the conversion from one encoding to the other.
   array<Byte>^asciiBytes = Encoding::Convert( unicode, ascii, unicodeBytes );
   
   // Convert the new Byte into[] a char and[] then into a string.
   array<Char>^asciiChars = gcnew array<Char>(ascii->GetCharCount( asciiBytes, 0, asciiBytes->Length ));
   ascii->GetChars( asciiBytes, 0, asciiBytes->Length, asciiChars, 0 );
   String^ asciiString = gcnew String( asciiChars );
   
   // Display the strings created before and after the conversion.
   Console::WriteLine( "Original String*: {0}", unicodeString );
   Console::WriteLine( "Ascii converted String*: {0}", asciiString );
}
// The example displays the following output:
//    Original string: This string contains the unicode character Pi (Π)
//    Ascii converted string: This string contains the unicode character Pi (?)
using System;
using System.Text;

class Example
{
   static void Main()
   {
      string unicodeString = "This string contains the unicode character Pi (\u03a0)";

      // Create two different encodings.
      Encoding ascii = Encoding.ASCII;
      Encoding unicode = Encoding.Unicode;

      // Convert the string into a byte array.
      byte[] unicodeBytes = unicode.GetBytes(unicodeString);

      // Perform the conversion from one encoding to the other.
      byte[] asciiBytes = Encoding.Convert(unicode, ascii, unicodeBytes);
         
      // Convert the new byte[] into a char[] and then into a string.
      char[] asciiChars = new char[ascii.GetCharCount(asciiBytes, 0, asciiBytes.Length)];
      ascii.GetChars(asciiBytes, 0, asciiBytes.Length, asciiChars, 0);
      string asciiString = new string(asciiChars);

      // Display the strings created before and after the conversion.
      Console.WriteLine("Original string: {0}", unicodeString);
      Console.WriteLine("Ascii converted string: {0}", asciiString);
   }
}
// The example displays the following output:
//    Original string: This string contains the unicode character Pi (Π)
//    Ascii converted string: This string contains the unicode character Pi (?)
Imports System.Text

Class Example
   Shared Sub Main()
      Dim unicodeString As String = "This string contains the unicode character Pi (" & ChrW(&H03A0) & ")"

      ' Create two different encodings.
      Dim ascii As Encoding = Encoding.ASCII
      Dim unicode As Encoding = Encoding.Unicode

      ' Convert the string into a byte array.
      Dim unicodeBytes As Byte() = unicode.GetBytes(unicodeString)

      ' Perform the conversion from one encoding to the other.
      Dim asciiBytes As Byte() = Encoding.Convert(unicode, ascii, unicodeBytes)

      ' Convert the new byte array into a char array and then into a string.
      Dim asciiChars(ascii.GetCharCount(asciiBytes, 0, asciiBytes.Length)-1) As Char
      ascii.GetChars(asciiBytes, 0, asciiBytes.Length, asciiChars, 0)
      Dim asciiString As New String(asciiChars)

      ' Display the strings created before and after the conversion.
      Console.WriteLine("Original string: {0}", unicodeString)
      Console.WriteLine("Ascii converted string: {0}", asciiString)
   End Sub
End Class
' The example displays the following output:
'    Original string: This string contains the unicode character Pi (Π)
'    Ascii converted string: This string contains the unicode character Pi (?)

下面的示例将字符串编码为一个字节数组,然后将一系列字节解码为字符数组。The following example encodes a string into an array of bytes, and then decodes a range of the bytes into an array of characters.

using namespace System;
using namespace System::Text;
void PrintCountsAndChars( array<Byte>^bytes, int index, int count, Encoding^ enc );
int main()
{
   
   // Create two instances of UTF32Encoding: one with little-endian byte order and one with big-endian byte order.
   Encoding^ u32LE = Encoding::GetEncoding( "utf-32" );
   Encoding^ u32BE = Encoding::GetEncoding( "utf-32BE" );
   
   // Use a 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)
   String^ myStr = "za\u0306\u01FD\u03B2";
   
   // Encode the string using the big-endian byte order.
   array<Byte>^barrBE = gcnew array<Byte>(u32BE->GetByteCount( myStr ));
   u32BE->GetBytes( myStr, 0, myStr->Length, barrBE, 0 );
   
   // Encode the string using the little-endian byte order.
   array<Byte>^barrLE = gcnew array<Byte>(u32LE->GetByteCount( myStr ));
   u32LE->GetBytes( myStr, 0, myStr->Length, barrLE, 0 );
   
   // Get the char counts, decode eight bytes starting at index 0,
   // and print out the counts and the resulting bytes.
   Console::Write( "BE array with BE encoding : " );
   PrintCountsAndChars( barrBE, 0, 8, u32BE );
   Console::Write( "LE array with LE encoding : " );
   PrintCountsAndChars( barrLE, 0, 8, u32LE );
}

void PrintCountsAndChars( array<Byte>^bytes, int index, int count, Encoding^ enc )
{
   
   // Display the name of the encoding used.
   Console::Write( "{0,-25} :", enc );
   
   // Display the exact character count.
   int iCC = enc->GetCharCount( bytes, index, count );
   Console::Write( " {0,-3}", iCC );
   
   // Display the maximum character count.
   int iMCC = enc->GetMaxCharCount( count );
   Console::Write( " {0,-3} :", iMCC );
   
   // Decode the bytes and display the characters.
   array<Char>^chars = enc->GetChars( bytes, index, count );
   
   // The following is an alternative way to decode the bytes:
   // Char[] chars = new Char[iCC];
   // enc->GetChars( bytes, index, count, chars, 0 );
   Console::WriteLine( chars );
}

/* 
This code produces the following output.  The question marks take the place of characters that cannot be displayed at the console.

BE array with BE encoding : System.Text.UTF32Encoding : 2   6   :za
LE array with LE encoding : System.Text.UTF32Encoding : 2   6   :za

*/
using System;
using System.Text;

public class SamplesEncoding  {

   public static void Main()  {

      // Create two instances of UTF32Encoding: one with little-endian byte order and one with big-endian byte order.
      Encoding u32LE = Encoding.GetEncoding( "utf-32" );
      Encoding u32BE = Encoding.GetEncoding( "utf-32BE" );

      // Use a 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)
      String myStr = "za\u0306\u01FD\u03B2";

      // Encode the string using the big-endian byte order.
      byte[] barrBE = new byte[u32BE.GetByteCount( myStr )];
      u32BE.GetBytes( myStr, 0, myStr.Length, barrBE, 0 );

      // Encode the string using the little-endian byte order.
      byte[] barrLE = new byte[u32LE.GetByteCount( myStr )];
      u32LE.GetBytes( myStr, 0, myStr.Length, barrLE, 0 );

      // Get the char counts, decode eight bytes starting at index 0,
      // and print out the counts and the resulting bytes.
      Console.Write( "BE array with BE encoding : " );
      PrintCountsAndChars( barrBE, 0, 8, u32BE );
      Console.Write( "LE array with LE encoding : " );
      PrintCountsAndChars( barrLE, 0, 8, u32LE );
   }

   public static void PrintCountsAndChars( byte[] bytes, int index, int count, Encoding enc )  {

      // Display the name of the encoding used.
      Console.Write( "{0,-25} :", enc.ToString() );

      // Display the exact character count.
      int iCC  = enc.GetCharCount( bytes, index, count );
      Console.Write( " {0,-3}", iCC );

      // Display the maximum character count.
      int iMCC = enc.GetMaxCharCount( count );
      Console.Write( " {0,-3} :", iMCC );

      // Decode the bytes and display the characters.
      char[] chars = enc.GetChars( bytes, index, count );

      // The following is an alternative way to decode the bytes:
      // char[] chars = new char[iCC];
      // enc.GetChars( bytes, index, count, chars, 0 );

      Console.WriteLine( chars );
   }
}


/* 
This code produces the following output.  The question marks take the place of characters that cannot be displayed at the console.

BE array with BE encoding : System.Text.UTF32Encoding : 2   6   :za
LE array with LE encoding : System.Text.UTF32Encoding : 2   6   :za

*/
Imports System.Text

Public Class SamplesEncoding   

   Public Shared Sub Main()

      ' Create two instances of UTF32Encoding: one with little-endian byte order and one with big-endian byte order.
      Dim u32LE As Encoding = Encoding.GetEncoding("utf-32")
      Dim u32BE As Encoding = Encoding.GetEncoding("utf-32BE")

      ' Use a 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)
      Dim myStr As String = "za" & ChrW(&H0306) & ChrW(&H01FD) & ChrW(&H03B2)

      ' Encode the string using the big-endian byte order.
      ' NOTE: In VB.NET, arrays contain one extra element by default.
      '       The following line creates barrBE with the exact number of elements required.
      Dim barrBE(u32BE.GetByteCount(myStr) - 1) As Byte
      u32BE.GetBytes(myStr, 0, myStr.Length, barrBE, 0)

      ' Encode the string using the little-endian byte order.
      ' NOTE: In VB.NET, arrays contain one extra element by default.
      '       The following line creates barrLE with the exact number of elements required.
      Dim barrLE(u32LE.GetByteCount(myStr) - 1) As Byte
      u32LE.GetBytes(myStr, 0, myStr.Length, barrLE, 0)

      ' Get the char counts, decode eight bytes starting at index 0,
      ' and print out the counts and the resulting bytes.
      Console.Write("BE array with BE encoding : ")
      PrintCountsAndChars(barrBE, 0, 8, u32BE)
      Console.Write("LE array with LE encoding : ")
      PrintCountsAndChars(barrLE, 0, 8, u32LE)

   End Sub


   Public Shared Sub PrintCountsAndChars(bytes() As Byte, index As Integer, count As Integer, enc As Encoding)

      ' Display the name of the encoding used.
      Console.Write("{0,-25} :", enc.ToString())

      ' Display the exact character count.
      Dim iCC As Integer = enc.GetCharCount(bytes, index, count)
      Console.Write(" {0,-3}", iCC)

      ' Display the maximum character count.
      Dim iMCC As Integer = enc.GetMaxCharCount(count)
      Console.Write(" {0,-3} :", iMCC)

      ' Decode the bytes.
      Dim chars As Char() = enc.GetChars(bytes, index, count)

      ' The following is an alternative way to decode the bytes:
      ' 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 chars(iCC - 1) As Char
      ' enc.GetChars( bytes, index, count, chars, 0 )

      ' Display the characters.
      Console.WriteLine(chars)

   End Sub

End Class


'This code produces the following output.  The question marks take the place of characters that cannot be displayed at the console.
'
'BE array with BE encoding : System.Text.UTF32Encoding : 2   6   :za
'LE array with LE encoding : System.Text.UTF32Encoding : 2   6   :za

注解

若要计算存储所生成的字符所需的确切数组大小 GetChars ,应使用 GetCharCount 方法。To calculate the exact array size required by GetChars to store the resulting characters, you should use the GetCharCount method. 若要计算最大数组大小,请使用 GetMaxCharCount 方法。To calculate the maximum array size, use the GetMaxCharCount method. GetCharCount方法通常允许分配较少的内存,而 GetMaxCharCount 方法的执行速度通常更快。The GetCharCount method generally allows allocation of less memory, while the GetMaxCharCount method generally executes faster.

GetChars(Byte[], Int32, Int32, Char[], Int32)从输入字节序列中获取字符。GetChars(Byte[], Int32, Int32, Char[], Int32) gets characters from an input byte sequence. Encoding.GetChars不同于 Decoder.GetChars ,因为 Encoding 需要离散转换,而 Decoder 为单个输入流上的多个传递设计。Encoding.GetChars is different than Decoder.GetChars because Encoding expects discrete conversions, while Decoder is designed for multiple passes on a single input stream.

如果要转换的数据仅在顺序块(如从流中读取的数据)中可用,或者如果数据量很大以致需要分为更小块,则应使用 Decoder Encoder GetDecoder 派生类的方法或方法提供的或 GetEncoderIf the data to be converted is available only in sequential blocks (such as data read from a stream) or if the amount of data is so large that it needs to be divided into smaller blocks, you should use the Decoder or the Encoder provided by the GetDecoder method or the GetEncoder method, respectively, of a derived class.

备注

此方法用于对 Unicode 字符进行操作,而不是针对任意二进制数据(如字节数组)。This method is intended to operate on Unicode characters, not on arbitrary binary data, such as byte arrays. 如果需要将任意二进制数据编码为文本,应使用诸如 uuencode 这样的协议,该协议是由等方法实现的 Convert.ToBase64CharArrayIf you need to encode arbitrary binary data into text, you should use a protocol such as uuencode, which is implemented by methods such as Convert.ToBase64CharArray.

GetCharCount方法确定多少个字符会导致对一个字节序列进行解码,并且该 GetChars 方法执行实际解码。The GetCharCount method determines how many characters result in decoding a sequence of bytes, and the GetChars method performs the actual decoding. Encoding.GetChars方法需要分离转换,这与方法不同, Decoder.GetChars 后者处理单个输入流上的多个传递。The Encoding.GetChars method expects discrete conversions, in contrast to the Decoder.GetChars method, which handles multiple passes on a single input stream.

支持和的多个版本 GetCharCount GetCharsSeveral versions of GetCharCount and GetChars are supported. 下面是有关使用这些方法的一些编程注意事项:The following are some programming considerations for use of these methods:

  • 您的应用程序可能需要从代码页解码多个输入字节,并使用多个调用处理这些字节。Your app might need to decode multiple input bytes from a code page and process the bytes using multiple calls. 在这种情况下,您可能需要维护两次调用之间的状态,因为在分批处理时,字节序列可能会中断。In this case, you probably need to maintain state between calls, because byte sequences can be interrupted when processed in batches. (例如,ISO-2022 移位序列的一部分可能结束一个 GetChars 调用并在下一次调用开始时继续 GetChars(For example, part of an ISO-2022 shift sequence may end one GetChars call and continue at the beginning of the next GetChars call. Encoding.GetChars将为那些不完整的序列调用回退,但 Decoder 会记住这些序列的后续调用。)Encoding.GetChars will call the fallback for those incomplete sequences, but Decoder will remember those sequences for the next call.)

  • 如果你的应用程序处理字符串输出,则 GetString 建议使用方法。If your app handles string outputs, the GetString method is recommended. 由于此方法必须检查字符串长度并分配一个缓冲区,因此它稍慢一些,但生成的 String 类型是首选的。Since this method must check string length and allocate a buffer, it is slightly slower, but the resulting String type is to be preferred.

  • 的字节版本 GetChars(Byte*, Int32, Char*, Int32) 允许一些快速的方法,尤其是对大缓冲区的多个调用。The byte version of GetChars(Byte*, Int32, Char*, Int32) allows some fast techniques, particularly with multiple calls to large buffers. 但请记住,此方法版本有时不安全,因为指针是必需的。Bear in mind, however, that this method version is sometimes unsafe, since pointers are required.

  • 如果你的应用程序必须转换大量数据,则应重新使用输出缓冲区。If your app must convert a large amount of data, it should reuse the output buffer. 在这种情况下, GetChars(Byte[], Int32, Int32, Char[], Int32) 支持输出字符缓冲区的版本是最佳选择。In this case, the GetChars(Byte[], Int32, Int32, Char[], Int32) version that supports output character buffers is the best choice.

  • 请考虑使用 Decoder.Convert 方法而不是 GetCharCountConsider using the Decoder.Convert method instead of GetCharCount. 转换方法尽可能多地转换数据,如果输出缓冲区太小,则会引发异常。The conversion method converts as much data as possible and throws an exception if the output buffer is too small. 对于流的连续解码,此方法通常是最佳选择。For continuous decoding of a stream, this method is often the best choice.

另请参阅

适用于

GetChars(Byte*, Int32, Char*, Int32)

重要

此 API 不符合 CLS。

在派生类中重写时,将一个字节序列(从指定的字节指针开始)解码为一组字符,并从指定的字符指针开始存储该组字符。When overridden in a derived class, decodes a sequence of bytes starting at the specified byte pointer into a set of characters that are stored starting at the specified character pointer.

public:
 virtual int GetChars(System::Byte* bytes, int byteCount, char* chars, int charCount);
[System.CLSCompliant(false)]
[System.Security.SecurityCritical]
public virtual int GetChars (byte* bytes, int byteCount, char* chars, int charCount);
[System.CLSCompliant(false)]
public virtual int GetChars (byte* bytes, int byteCount, char* chars, int charCount);
public virtual int GetChars (byte* bytes, int byteCount, char* chars, int charCount);
[System.CLSCompliant(false)]
[System.Runtime.InteropServices.ComVisible(false)]
public virtual int GetChars (byte* bytes, int byteCount, char* chars, int charCount);
[System.CLSCompliant(false)]
[System.Security.SecurityCritical]
[System.Runtime.InteropServices.ComVisible(false)]
public virtual int GetChars (byte* bytes, int byteCount, char* chars, int charCount);
[<System.CLSCompliant(false)>]
[<System.Security.SecurityCritical>]
abstract member GetChars : nativeptr<byte> * int * nativeptr<char> * int -> int
override this.GetChars : nativeptr<byte> * int * nativeptr<char> * int -> int
[<System.CLSCompliant(false)>]
abstract member GetChars : nativeptr<byte> * int * nativeptr<char> * int -> int
override this.GetChars : nativeptr<byte> * int * nativeptr<char> * int -> int
abstract member GetChars : nativeptr<byte> * int * nativeptr<char> * int -> int
override this.GetChars : nativeptr<byte> * int * nativeptr<char> * int -> int
[<System.CLSCompliant(false)>]
[<System.Runtime.InteropServices.ComVisible(false)>]
abstract member GetChars : nativeptr<byte> * int * nativeptr<char> * int -> int
override this.GetChars : nativeptr<byte> * int * nativeptr<char> * int -> int
[<System.CLSCompliant(false)>]
[<System.Security.SecurityCritical>]
[<System.Runtime.InteropServices.ComVisible(false)>]
abstract member GetChars : nativeptr<byte> * int * nativeptr<char> * int -> int
override this.GetChars : nativeptr<byte> * int * nativeptr<char> * int -> int

参数

bytes
Byte*

指向第一个要解码的字节的指针。A pointer to the first byte to decode.

byteCount
Int32

要解码的字节数。The number of bytes to decode.

chars
Char*

一个指针,指向开始写入所产生的字符集的位置。A pointer to the location at which to start writing the resulting set of characters.

charCount
Int32

要写入的最大字符数。The maximum number of characters to write.

返回

Int32

在由 chars 参数指示的位置处写入的实际字符数。The actual number of characters written at the location indicated by the chars parameter.

属性

例外

bytesnullbytes is null.

-or-

charsnullchars is null.

byteCountcharCount 小于零。byteCount or charCount is less than zero.

charCount 少于所产生的字符数。charCount is less than the resulting number of characters.

发生回退(有关详细信息,请参阅采用 .NET 的字符编码A fallback occurred (for more information, see Character Encoding in .NET)

-和--and-

DecoderFallback 设置为 DecoderExceptionFallbackDecoderFallback is set to DecoderExceptionFallback.

注解

若要计算 GetChars 存储所生成的字符所需的确切数组大小,应使用 GetCharCount 方法。To calculate the exact array size that GetChars requires to store the resulting characters, you should use the GetCharCount method. 若要计算最大数组大小,请使用 GetMaxCharCount 方法。To calculate the maximum array size, use the GetMaxCharCount method. GetCharCount方法通常允许分配较少的内存,而 GetMaxCharCount 方法的执行速度通常更快。The GetCharCount method generally allows allocation of less memory, while the GetMaxCharCount method generally executes faster.

Encoding.GetChars从输入字节序列中获取字符。Encoding.GetChars gets characters from an input byte sequence. Encoding.GetChars不同于 Decoder.GetChars ,因为 Encoding 需要离散转换,而 Decoder 为单个输入流上的多个传递设计。Encoding.GetChars is different than Decoder.GetChars because Encoding expects discrete conversions, while Decoder is designed for multiple passes on a single input stream.

如果要转换的数据仅在 (如从流中读取的数据) 的顺序块中可用,或者如果数据量很大,它需要划分为较小的块,则应使用DecoderEncoder提供对象GetDecoderGetEncoder方法,分别的派生类。If the data to be converted is available only in sequential blocks (such as data read from a stream) or if the amount of data is so large that it needs to be divided into smaller blocks, you should use the Decoder or the Encoder object provided by the GetDecoder or the GetEncoder method, respectively, of a derived class.

备注

此方法用于对 Unicode 字符进行操作,而不是针对任意二进制数据(如字节数组)。This method is intended to operate on Unicode characters, not on arbitrary binary data, such as byte arrays. 如果需要将任意二进制数据编码为文本,应使用诸如 uuencode 这样的协议,该协议是由等方法实现的 Convert.ToBase64CharArrayIf you need to encode arbitrary binary data into text, you should use a protocol such as uuencode, which is implemented by methods such as Convert.ToBase64CharArray.

GetCharCount方法确定多少个字符会导致对一个字节序列进行解码,并且该 GetChars 方法执行实际解码。The GetCharCount method determines how many characters result in decoding a sequence of bytes, and the GetChars method performs the actual decoding. Encoding.GetChars方法需要分离转换,这与方法不同, Decoder.GetChars 后者处理单个输入流上的多个传递。The Encoding.GetChars method expects discrete conversions, in contrast to the Decoder.GetChars method, which handles multiple passes on a single input stream.

支持和的多个版本 GetCharCount GetCharsSeveral versions of GetCharCount and GetChars are supported. 下面是有关使用这些方法的一些编程注意事项:The following are some programming considerations for use of these methods:

  • 您的应用程序可能需要从代码页解码多个输入字节,并使用多个调用处理这些字节。Your app might need to decode multiple input bytes from a code page and process the bytes using multiple calls. 在这种情况下,您可能需要维护两次调用之间的状态,因为在分批处理时,字节序列可能会中断。In this case, you probably need to maintain state between calls, because byte sequences can be interrupted when processed in batches. (例如,ISO-2022 移位序列的一部分可能结束一个 GetChars 调用并在下一次调用开始时继续 GetChars(For example, part of an ISO-2022 shift sequence may end one GetChars call and continue at the beginning of the next GetChars call. Encoding.GetChars将为那些不完整的序列调用回退,但 Decoder 会记住这些序列的后续调用。)Encoding.GetChars will call the fallback for those incomplete sequences, but Decoder will remember those sequences for the next call.)

  • 如果你的应用程序处理字符串输出,则 GetString 建议使用方法。If your app handles string outputs, the GetString method is recommended. 由于此方法必须检查字符串长度并分配一个缓冲区,因此它稍慢一些,但生成的 String 类型是首选的。Since this method must check string length and allocate a buffer, it is slightly slower, but the resulting String type is to be preferred.

  • 的字节版本 GetChars(Byte*, Int32, Char*, Int32) 允许一些快速的方法,尤其是对大缓冲区的多个调用。The byte version of GetChars(Byte*, Int32, Char*, Int32) allows some fast techniques, particularly with multiple calls to large buffers. 但请记住,此方法版本有时不安全,因为指针是必需的。Bear in mind, however, that this method version is sometimes unsafe, since pointers are required.

  • 如果你的应用程序必须转换大量数据,则应重新使用输出缓冲区。If your app must convert a large amount of data, it should reuse the output buffer. 在这种情况下, GetChars(Byte[], Int32, Int32, Char[], Int32) 支持输出字符缓冲区的版本是最佳选择。In this case, the GetChars(Byte[], Int32, Int32, Char[], Int32) version that supports output character buffers is the best choice.

  • 请考虑使用 Decoder.Convert 方法而不是 GetCharCountConsider using the Decoder.Convert method instead of GetCharCount. 转换方法尽可能多地转换数据,如果输出缓冲区太小,则会引发异常。The conversion method converts as much data as possible and throws an exception if the output buffer is too small. 对于流的连续解码,此方法通常是最佳选择。For continuous decoding of a stream, this method is often the best choice.

另请参阅

适用于

GetChars(ReadOnlySpan<Byte>, Span<Char>)

在派生类中重写时,将指定只读字节范围中的所有字节解码为字符范围。When overridden in a derived class, decodes all the bytes in the specified read-only byte span into a character span.

public:
 virtual int GetChars(ReadOnlySpan<System::Byte> bytes, Span<char> chars);
public virtual int GetChars (ReadOnlySpan<byte> bytes, Span<char> chars);
abstract member GetChars : ReadOnlySpan<byte> * Span<char> -> int
override this.GetChars : ReadOnlySpan<byte> * Span<char> -> int
Public Overridable Function GetChars (bytes As ReadOnlySpan(Of Byte), chars As Span(Of Char)) As Integer

参数

bytes
ReadOnlySpan<Byte>

包含要解码的字节序列的只读范围。A read-only span containing the sequence of bytes to decode.

chars
Span<Char>

接收已解码字节的字符范围。The character span receiving the decoded bytes.

返回

Int32

已解码的字节数。The number of decoded bytes.

注解

Encoding.GetChars从输入字节跨度中获取字符。Encoding.GetChars gets characters from an input byte span. Encoding.GetChars不同于 Decoder.GetChars ,因为 Encoding 需要离散转换,而 Decoder 为单个输入流上的多个传递设计。Encoding.GetChars is different than Decoder.GetChars because Encoding expects discrete conversions, while Decoder is designed for multiple passes on a single input stream.

如果要转换的数据仅在顺序块(如从流中读取的数据)中可用,或者如果数据量很大以致需要分为更小块,则应使用 Decoder Encoder GetDecoder 派生类的方法或方法提供的或 GetEncoderIf the data to be converted is available only in sequential blocks (such as data read from a stream) or if the amount of data is so large that it needs to be divided into smaller blocks, you should use the Decoder or the Encoder provided by the GetDecoder method or the GetEncoder method, respectively, of a derived class.

GetCharCount方法确定多少个字符会导致对一个字节序列进行解码,并且该 GetChars 方法执行实际解码。The GetCharCount method determines how many characters result in decoding a sequence of bytes, and the GetChars method performs the actual decoding. Encoding.GetChars方法需要分离转换,这与方法不同, Decoder.GetChars 后者处理单个输入流上的多个传递。The Encoding.GetChars method expects discrete conversions, in contrast to the Decoder.GetChars method, which handles multiple passes on a single input stream.

支持和的多个版本 GetCharCount GetCharsSeveral versions of GetCharCount and GetChars are supported. 下面是有关使用这些方法的一些编程注意事项:The following are some programming considerations for use of these methods:

  • 您的应用程序可能需要从代码页解码多个输入字节,并使用多个调用处理这些字节。Your app might need to decode multiple input bytes from a code page and process the bytes using multiple calls. 在这种情况下,您可能需要维护两次调用之间的状态,因为在分批处理时,字节序列可能会中断。In this case, you probably need to maintain state between calls, because byte sequences can be interrupted when processed in batches. (例如,ISO-2022 移位序列的一部分可能结束一个 GetChars 调用并在下一次调用开始时继续 GetChars(For example, part of an ISO-2022 shift sequence may end one GetChars call and continue at the beginning of the next GetChars call. Encoding.GetChars将为那些不完整的序列调用回退,但 Decoder 会记住这些序列的后续调用。)Encoding.GetChars will call the fallback for those incomplete sequences, but Decoder will remember those sequences for the next call.)

  • 如果你的应用程序处理字符串输出,则建议使用 GetString 方法。If your app handles string outputs, it is recommended to use the GetString method. 由于此方法必须检查字符串长度并分配一个缓冲区,因此它稍慢一些,但生成的 String 类型是首选的。Since this method must check string length and allocate a buffer, it is slightly slower, but the resulting String type is to be preferred.

  • 的字节版本 GetChars(Byte*, Int32, Char*, Int32) 允许一些快速的方法,尤其是对大缓冲区的多个调用。The byte version of GetChars(Byte*, Int32, Char*, Int32) allows some fast techniques, particularly with multiple calls to large buffers. 但请记住,此方法版本有时不安全,因为指针是必需的。Bear in mind, however, that this method version is sometimes unsafe, since pointers are required.

  • 如果你的应用程序必须转换大量数据,则应重新使用输出缓冲区。If your app must convert a large amount of data, it should reuse the output buffer. 在这种情况下, GetChars(Byte[], Int32, Int32, Char[], Int32) 支持输出字符缓冲区的版本是最佳选择。In this case, the GetChars(Byte[], Int32, Int32, Char[], Int32) version that supports output character buffers is the best choice.

  • 请考虑使用 Decoder.Convert 方法而不是 GetCharCountConsider using the Decoder.Convert method instead of GetCharCount. 转换方法尽可能多地转换数据,如果输出缓冲区太小,则会引发异常。The conversion method converts as much data as possible and throws an exception if the output buffer is too small. 对于流的连续解码,此方法通常是最佳选择。For continuous decoding of a stream, this method is often the best choice.

适用于

GetChars(Byte[], Int32, Int32)

在派生类中重写时,将指定字节数组中的一个字节序列解码为一组字符。When overridden in a derived class, decodes a sequence of bytes from the specified byte array into a set of characters.

public:
 virtual cli::array <char> ^ GetChars(cli::array <System::Byte> ^ bytes, int index, int count);
public virtual char[] GetChars (byte[] bytes, int index, int count);
abstract member GetChars : byte[] * int * int -> char[]
override this.GetChars : byte[] * int * int -> char[]
Public Overridable Function GetChars (bytes As Byte(), index As Integer, count As Integer) As Char()

参数

bytes
Byte[]

包含要解码的字节序列的字节数组。The byte array containing the sequence of bytes to decode.

index
Int32

第一个要解码的字节的索引。The index of the first byte to decode.

count
Int32

要解码的字节数。The number of bytes to decode.

返回

Char[]

一个字节数组,包含对指定的字节序列进行解码的结果。A character array containing the results of decoding the specified sequence of bytes.

例外

bytesnullbytes is null.

indexcount 小于零。index or count is less than zero.

-or-

indexcount 不表示 bytes 中的有效范围。index and count do not denote a valid range in bytes.

发生回退(有关详细信息,请参阅采用 .NET 的字符编码A fallback occurred (for more information, see Character Encoding in .NET)

-和--and-

DecoderFallback 设置为 DecoderExceptionFallbackDecoderFallback is set to DecoderExceptionFallback.

示例

下面的示例将字符串编码为一个字节数组,然后将一系列字节解码为字符数组。The following example encodes a string into an array of bytes, and then decodes a range of the bytes into an array of characters.

using namespace System;
using namespace System::Text;
void PrintCountsAndChars( array<Byte>^bytes, int index, int count, Encoding^ enc );
int main()
{
   
   // Create two instances of UTF32Encoding: one with little-endian byte order and one with big-endian byte order.
   Encoding^ u32LE = Encoding::GetEncoding( "utf-32" );
   Encoding^ u32BE = Encoding::GetEncoding( "utf-32BE" );
   
   // Use a 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)
   String^ myStr = "za\u0306\u01FD\u03B2";
   
   // Encode the string using the big-endian byte order.
   array<Byte>^barrBE = gcnew array<Byte>(u32BE->GetByteCount( myStr ));
   u32BE->GetBytes( myStr, 0, myStr->Length, barrBE, 0 );
   
   // Encode the string using the little-endian byte order.
   array<Byte>^barrLE = gcnew array<Byte>(u32LE->GetByteCount( myStr ));
   u32LE->GetBytes( myStr, 0, myStr->Length, barrLE, 0 );
   
   // Get the char counts, decode eight bytes starting at index 0,
   // and print out the counts and the resulting bytes.
   Console::Write( "BE array with BE encoding : " );
   PrintCountsAndChars( barrBE, 0, 8, u32BE );
   Console::Write( "LE array with LE encoding : " );
   PrintCountsAndChars( barrLE, 0, 8, u32LE );
}

void PrintCountsAndChars( array<Byte>^bytes, int index, int count, Encoding^ enc )
{
   
   // Display the name of the encoding used.
   Console::Write( "{0,-25} :", enc );
   
   // Display the exact character count.
   int iCC = enc->GetCharCount( bytes, index, count );
   Console::Write( " {0,-3}", iCC );
   
   // Display the maximum character count.
   int iMCC = enc->GetMaxCharCount( count );
   Console::Write( " {0,-3} :", iMCC );
   
   // Decode the bytes and display the characters.
   array<Char>^chars = enc->GetChars( bytes, index, count );
   
   // The following is an alternative way to decode the bytes:
   // Char[] chars = new Char[iCC];
   // enc->GetChars( bytes, index, count, chars, 0 );
   Console::WriteLine( chars );
}

/* 
This code produces the following output.  The question marks take the place of characters that cannot be displayed at the console.

BE array with BE encoding : System.Text.UTF32Encoding : 2   6   :za
LE array with LE encoding : System.Text.UTF32Encoding : 2   6   :za

*/
using System;
using System.Text;

public class SamplesEncoding  {

   public static void Main()  {

      // Create two instances of UTF32Encoding: one with little-endian byte order and one with big-endian byte order.
      Encoding u32LE = Encoding.GetEncoding( "utf-32" );
      Encoding u32BE = Encoding.GetEncoding( "utf-32BE" );

      // Use a 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)
      String myStr = "za\u0306\u01FD\u03B2";

      // Encode the string using the big-endian byte order.
      byte[] barrBE = new byte[u32BE.GetByteCount( myStr )];
      u32BE.GetBytes( myStr, 0, myStr.Length, barrBE, 0 );

      // Encode the string using the little-endian byte order.
      byte[] barrLE = new byte[u32LE.GetByteCount( myStr )];
      u32LE.GetBytes( myStr, 0, myStr.Length, barrLE, 0 );

      // Get the char counts, decode eight bytes starting at index 0,
      // and print out the counts and the resulting bytes.
      Console.Write( "BE array with BE encoding : " );
      PrintCountsAndChars( barrBE, 0, 8, u32BE );
      Console.Write( "LE array with LE encoding : " );
      PrintCountsAndChars( barrLE, 0, 8, u32LE );
   }

   public static void PrintCountsAndChars( byte[] bytes, int index, int count, Encoding enc )  {

      // Display the name of the encoding used.
      Console.Write( "{0,-25} :", enc.ToString() );

      // Display the exact character count.
      int iCC  = enc.GetCharCount( bytes, index, count );
      Console.Write( " {0,-3}", iCC );

      // Display the maximum character count.
      int iMCC = enc.GetMaxCharCount( count );
      Console.Write( " {0,-3} :", iMCC );

      // Decode the bytes and display the characters.
      char[] chars = enc.GetChars( bytes, index, count );

      // The following is an alternative way to decode the bytes:
      // char[] chars = new char[iCC];
      // enc.GetChars( bytes, index, count, chars, 0 );

      Console.WriteLine( chars );
   }
}


/* 
This code produces the following output.  The question marks take the place of characters that cannot be displayed at the console.

BE array with BE encoding : System.Text.UTF32Encoding : 2   6   :za
LE array with LE encoding : System.Text.UTF32Encoding : 2   6   :za

*/
Imports System.Text

Public Class SamplesEncoding   

   Public Shared Sub Main()

      ' Create two instances of UTF32Encoding: one with little-endian byte order and one with big-endian byte order.
      Dim u32LE As Encoding = Encoding.GetEncoding("utf-32")
      Dim u32BE As Encoding = Encoding.GetEncoding("utf-32BE")

      ' Use a 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)
      Dim myStr As String = "za" & ChrW(&H0306) & ChrW(&H01FD) & ChrW(&H03B2)

      ' Encode the string using the big-endian byte order.
      ' NOTE: In VB.NET, arrays contain one extra element by default.
      '       The following line creates barrBE with the exact number of elements required.
      Dim barrBE(u32BE.GetByteCount(myStr) - 1) As Byte
      u32BE.GetBytes(myStr, 0, myStr.Length, barrBE, 0)

      ' Encode the string using the little-endian byte order.
      ' NOTE: In VB.NET, arrays contain one extra element by default.
      '       The following line creates barrLE with the exact number of elements required.
      Dim barrLE(u32LE.GetByteCount(myStr) - 1) As Byte
      u32LE.GetBytes(myStr, 0, myStr.Length, barrLE, 0)

      ' Get the char counts, decode eight bytes starting at index 0,
      ' and print out the counts and the resulting bytes.
      Console.Write("BE array with BE encoding : ")
      PrintCountsAndChars(barrBE, 0, 8, u32BE)
      Console.Write("LE array with LE encoding : ")
      PrintCountsAndChars(barrLE, 0, 8, u32LE)

   End Sub


   Public Shared Sub PrintCountsAndChars(bytes() As Byte, index As Integer, count As Integer, enc As Encoding)

      ' Display the name of the encoding used.
      Console.Write("{0,-25} :", enc.ToString())

      ' Display the exact character count.
      Dim iCC As Integer = enc.GetCharCount(bytes, index, count)
      Console.Write(" {0,-3}", iCC)

      ' Display the maximum character count.
      Dim iMCC As Integer = enc.GetMaxCharCount(count)
      Console.Write(" {0,-3} :", iMCC)

      ' Decode the bytes.
      Dim chars As Char() = enc.GetChars(bytes, index, count)

      ' The following is an alternative way to decode the bytes:
      ' 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 chars(iCC - 1) As Char
      ' enc.GetChars( bytes, index, count, chars, 0 )

      ' Display the characters.
      Console.WriteLine(chars)

   End Sub

End Class


'This code produces the following output.  The question marks take the place of characters that cannot be displayed at the console.
'
'BE array with BE encoding : System.Text.UTF32Encoding : 2   6   :za
'LE array with LE encoding : System.Text.UTF32Encoding : 2   6   :za

注解

Encoding.GetChars从输入字节序列中获取字符。Encoding.GetChars gets characters from an input byte sequence. Encoding.GetChars不同于 Decoder.GetChars ,因为 Encoding 需要离散转换,而 Decoder 为单个输入流上的多个传递设计。Encoding.GetChars is different than Decoder.GetChars because Encoding expects discrete conversions, while Decoder is designed for multiple passes on a single input stream.

如果要转换的数据仅在顺序块(如从流中读取的数据)中可用,或者如果数据量很大以致需要分为更小块,则应使用 Decoder Encoder GetDecoder 派生类的方法或方法提供的或 GetEncoderIf the data to be converted is available only in sequential blocks (such as data read from a stream) or if the amount of data is so large that it needs to be divided into smaller blocks, you should use the Decoder or the Encoder provided by the GetDecoder method or the GetEncoder method, respectively, of a derived class.

备注

此方法用于对 Unicode 字符进行操作,而不是针对任意二进制数据(如字节数组)。This method is intended to operate on Unicode characters, not on arbitrary binary data, such as byte arrays. 如果需要将任意二进制数据编码为文本,应使用诸如 uuencode 这样的协议,该协议是由等方法实现的 Convert.ToBase64CharArrayIf you need to encode arbitrary binary data into text, you should use a protocol such as uuencode, which is implemented by methods such as Convert.ToBase64CharArray.

GetCharCount方法确定多少个字符会导致对一个字节序列进行解码,并且该 GetChars 方法执行实际解码。The GetCharCount method determines how many characters result in decoding a sequence of bytes, and the GetChars method performs the actual decoding. Encoding.GetChars方法需要分离转换,这与方法不同, Decoder.GetChars 后者处理单个输入流上的多个传递。The Encoding.GetChars method expects discrete conversions, in contrast to the Decoder.GetChars method, which handles multiple passes on a single input stream.

支持和的多个版本 GetCharCount GetCharsSeveral versions of GetCharCount and GetChars are supported. 下面是有关使用这些方法的一些编程注意事项:The following are some programming considerations for use of these methods:

  • 您的应用程序可能需要从代码页解码多个输入字节,并使用多个调用处理这些字节。Your app might need to decode multiple input bytes from a code page and process the bytes using multiple calls. 在这种情况下,您可能需要维护两次调用之间的状态,因为在分批处理时,字节序列可能会中断。In this case, you probably need to maintain state between calls, because byte sequences can be interrupted when processed in batches. (例如,ISO-2022 移位序列的一部分可能结束一个 GetChars 调用并在下一次调用开始时继续 GetChars(For example, part of an ISO-2022 shift sequence may end one GetChars call and continue at the beginning of the next GetChars call. Encoding.GetChars将为那些不完整的序列调用回退,但 Decoder 会记住这些序列的后续调用。)Encoding.GetChars will call the fallback for those incomplete sequences, but Decoder will remember those sequences for the next call.)

  • 如果你的应用程序处理字符串输出,则建议使用 GetString 方法。If your app handles string outputs, it is recommended to use the GetString method. 由于此方法必须检查字符串长度并分配一个缓冲区,因此它稍慢一些,但生成的 String 类型是首选的。Since this method must check string length and allocate a buffer, it is slightly slower, but the resulting String type is to be preferred.

  • 的字节版本 GetChars(Byte*, Int32, Char*, Int32) 允许一些快速的方法,尤其是对大缓冲区的多个调用。The byte version of GetChars(Byte*, Int32, Char*, Int32) allows some fast techniques, particularly with multiple calls to large buffers. 但请记住,此方法版本有时不安全,因为指针是必需的。Bear in mind, however, that this method version is sometimes unsafe, since pointers are required.

  • 如果你的应用程序必须转换大量数据,则应重新使用输出缓冲区。If your app must convert a large amount of data, it should reuse the output buffer. 在这种情况下, GetChars(Byte[], Int32, Int32, Char[], Int32) 支持输出字符缓冲区的版本是最佳选择。In this case, the GetChars(Byte[], Int32, Int32, Char[], Int32) version that supports output character buffers is the best choice.

  • 请考虑使用 Decoder.Convert 方法而不是 GetCharCountConsider using the Decoder.Convert method instead of GetCharCount. 转换方法尽可能多地转换数据,如果输出缓冲区太小,则会引发异常。The conversion method converts as much data as possible and throws an exception if the output buffer is too small. 对于流的连续解码,此方法通常是最佳选择。For continuous decoding of a stream, this method is often the best choice.

另请参阅

适用于

GetChars(Byte[])

在派生类中重写时,将指定字节数组中的所有字节解码为一组字符。When overridden in a derived class, decodes all the bytes in the specified byte array into a set of characters.

public:
 virtual cli::array <char> ^ GetChars(cli::array <System::Byte> ^ bytes);
public virtual char[] GetChars (byte[] bytes);
abstract member GetChars : byte[] -> char[]
override this.GetChars : byte[] -> char[]
Public Overridable Function GetChars (bytes As Byte()) As Char()

参数

bytes
Byte[]

包含要解码的字节序列的字节数组。The byte array containing the sequence of bytes to decode.

返回

Char[]

一个字节数组,包含对指定的字节序列进行解码的结果。A character array containing the results of decoding the specified sequence of bytes.

例外

bytesnullbytes is null.

发生回退(有关详细信息,请参阅采用 .NET 的字符编码A fallback occurred (for more information, see Character Encoding in .NET)

-和--and-

DecoderFallback 设置为 DecoderExceptionFallbackDecoderFallback is set to DecoderExceptionFallback.

示例

下面的示例将字符串编码为一个字节数组,然后将这些字节解码为一个字符数组。The following example encodes a string into an array of bytes, and then decodes the bytes into an array of characters.

using namespace System;
using namespace System::Text;
void PrintCountsAndChars( array<Byte>^bytes, Encoding^ enc );
int main()
{
   
   // Create two instances of UTF32Encoding: one with little-endian byte order and one with big-endian byte order.
   Encoding^ u32LE = Encoding::GetEncoding( "utf-32" );
   Encoding^ u32BE = Encoding::GetEncoding( "utf-32BE" );
   
   // Use a 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)
   String^ myStr = "za\u0306\u01FD\u03B2";
   
   // Encode the string using the big-endian byte order.
   array<Byte>^barrBE = gcnew array<Byte>(u32BE->GetByteCount( myStr ));
   u32BE->GetBytes( myStr, 0, myStr->Length, barrBE, 0 );
   
   // Encode the string using the little-endian byte order.
   array<Byte>^barrLE = gcnew array<Byte>(u32LE->GetByteCount( myStr ));
   u32LE->GetBytes( myStr, 0, myStr->Length, barrLE, 0 );
   
   // Get the char counts, and decode the byte arrays.
   Console::Write( "BE array with BE encoding : " );
   PrintCountsAndChars( barrBE, u32BE );
   Console::Write( "LE array with LE encoding : " );
   PrintCountsAndChars( barrLE, u32LE );
}

void PrintCountsAndChars( array<Byte>^bytes, Encoding^ enc )
{
   
   // Display the name of the encoding used.
   Console::Write( "{0,-25} :", enc );
   
   // Display the exact character count.
   int iCC = enc->GetCharCount( bytes );
   Console::Write( " {0,-3}", iCC );
   
   // Display the maximum character count.
   int iMCC = enc->GetMaxCharCount( bytes->Length );
   Console::Write( " {0,-3} :", iMCC );
   
   // Decode the bytes and display the characters.
   array<Char>^chars = enc->GetChars( bytes );
   Console::WriteLine( chars );
}

/* 
This code produces the following output.  The question marks take the place of characters that cannot be displayed at the console.

BE array with BE encoding : System.Text.UTF32Encoding : 5   12  :zăǽβ
LE array with LE encoding : System.Text.UTF32Encoding : 5   12  :zăǽβ

*/
using System;
using System.Text;

public class SamplesEncoding  {

   public static void Main()  {

      // Create two instances of UTF32Encoding: one with little-endian byte order and one with big-endian byte order.
      Encoding u32LE = Encoding.GetEncoding( "utf-32" );
      Encoding u32BE = Encoding.GetEncoding( "utf-32BE" );

      // Use a 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)
      String myStr = "za\u0306\u01FD\u03B2";

      // Encode the string using the big-endian byte order.
      byte[] barrBE = new byte[u32BE.GetByteCount( myStr )];
      u32BE.GetBytes( myStr, 0, myStr.Length, barrBE, 0 );

      // Encode the string using the little-endian byte order.
      byte[] barrLE = new byte[u32LE.GetByteCount( myStr )];
      u32LE.GetBytes( myStr, 0, myStr.Length, barrLE, 0 );

      // Get the char counts, and decode the byte arrays.
      Console.Write( "BE array with BE encoding : " );
      PrintCountsAndChars( barrBE, u32BE );
      Console.Write( "LE array with LE encoding : " );
      PrintCountsAndChars( barrLE, u32LE );
   }

   public static void PrintCountsAndChars( byte[] bytes, Encoding enc )  {

      // Display the name of the encoding used.
      Console.Write( "{0,-25} :", enc.ToString() );

      // Display the exact character count.
      int iCC  = enc.GetCharCount( bytes );
      Console.Write( " {0,-3}", iCC );

      // Display the maximum character count.
      int iMCC = enc.GetMaxCharCount( bytes.Length );
      Console.Write( " {0,-3} :", iMCC );

      // Decode the bytes and display the characters.
      char[] chars = enc.GetChars( bytes );
      Console.WriteLine( chars );
   }
}


/* 
This code produces the following output.  The question marks take the place of characters that cannot be displayed at the console.

BE array with BE encoding : System.Text.UTF32Encoding : 5   12  :zăǽβ
LE array with LE encoding : System.Text.UTF32Encoding : 5   12  :zăǽβ

*/
Imports System.Text

Public Class SamplesEncoding   

   Public Shared Sub Main()

      ' Create two instances of UTF32Encoding: one with little-endian byte order and one with big-endian byte order.
      Dim u32LE As Encoding = Encoding.GetEncoding("utf-32")
      Dim u32BE As Encoding = Encoding.GetEncoding("utf-32BE")

      ' Use a 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)
      Dim myStr As String = "za" & ChrW(&H0306) & ChrW(&H01FD) & ChrW(&H03B2) 

      ' Encode the string using the big-endian byte order.
      ' 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 barrBE(u32BE.GetByteCount(myStr) - 1) As Byte
      u32BE.GetBytes(myStr, 0, myStr.Length, barrBE, 0)

      ' Encode the string using the little-endian byte order.
      ' 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 barrLE(u32LE.GetByteCount(myStr) - 1) As Byte
      u32LE.GetBytes(myStr, 0, myStr.Length, barrLE, 0)

      ' Get the char counts, and decode the byte arrays.
      Console.Write("BE array with BE encoding : ")
      PrintCountsAndChars(barrBE, u32BE)
      Console.Write("LE array with LE encoding : ")
      PrintCountsAndChars(barrLE, u32LE)

   End Sub


   Public Shared Sub PrintCountsAndChars(bytes() As Byte, enc As Encoding)

      ' Display the name of the encoding used.
      Console.Write("{0,-25} :", enc.ToString())

      ' Display the exact character count.
      Dim iCC As Integer = enc.GetCharCount(bytes)
      Console.Write(" {0,-3}", iCC)

      ' Display the maximum character count.
      Dim iMCC As Integer = enc.GetMaxCharCount(bytes.Length)
      Console.Write(" {0,-3} :", iMCC)

      ' Decode the bytes and display the characters.
      Dim chars As Char() = enc.GetChars(bytes)
      Console.WriteLine(chars)

   End Sub

End Class


'This code produces the following output.  The question marks take the place of characters that cannot be displayed at the console.
'
'BE array with BE encoding : System.Text.UTF32Encoding : 5   12  :zăǽβ
'LE array with LE encoding : System.Text.UTF32Encoding : 5   12  :zăǽβ

注解

Encoding.GetChars从输入字节序列中获取字符。Encoding.GetChars gets characters from an input byte sequence. Encoding.GetChars不同于 Decoder.GetChars ,因为 Encoding 需要离散转换,而 Decoder 为单个输入流上的多个传递设计。Encoding.GetChars is different than Decoder.GetChars because Encoding expects discrete conversions, while Decoder is designed for multiple passes on a single input stream.

如果要转换的数据仅在顺序块(如从流中读取的数据)中可用,或者如果数据量很大以致需要分为更小块,则应使用 Decoder Encoder GetDecoder 派生类的方法或方法提供的或 GetEncoderIf the data to be converted is available only in sequential blocks (such as data read from a stream) or if the amount of data is so large that it needs to be divided into smaller blocks, you should use the Decoder or the Encoder provided by the GetDecoder method or the GetEncoder method, respectively, of a derived class.

备注

此方法用于对 Unicode 字符进行操作,而不是针对任意二进制数据(如字节数组)。This method is intended to operate on Unicode characters, not on arbitrary binary data, such as byte arrays. 如果需要将任意二进制数据编码为文本,应使用诸如 uuencode 这样的协议,该协议是由等方法实现的 Convert.ToBase64CharArrayIf you need to encode arbitrary binary data into text, you should use a protocol such as uuencode, which is implemented by methods such as Convert.ToBase64CharArray.

GetCharCount方法确定多少个字符会导致对一个字节序列进行解码,并且该 GetChars 方法执行实际解码。The GetCharCount method determines how many characters result in decoding a sequence of bytes, and the GetChars method performs the actual decoding. Encoding.GetChars方法需要分离转换,这与方法不同, Decoder.GetChars 后者处理单个输入流上的多个传递。The Encoding.GetChars method expects discrete conversions, in contrast to the Decoder.GetChars method, which handles multiple passes on a single input stream.

支持和的多个版本 GetCharCount GetCharsSeveral versions of GetCharCount and GetChars are supported. 下面是有关使用这些方法的一些编程注意事项:The following are some programming considerations for use of these methods:

  • 您的应用程序可能需要从代码页解码多个输入字节,并使用多个调用处理这些字节。Your app might need to decode multiple input bytes from a code page and process the bytes using multiple calls. 在这种情况下,您可能需要维护两次调用之间的状态,因为在分批处理时,字节序列可能会中断。In this case, you probably need to maintain state between calls, because byte sequences can be interrupted when processed in batches. (例如,ISO-2022 移位序列的一部分可能结束一个 GetChars 调用并在下一次调用开始时继续 GetChars(For example, part of an ISO-2022 shift sequence may end one GetChars call and continue at the beginning of the next GetChars call. Encoding.GetChars将为那些不完整的序列调用回退,但 Decoder 会记住这些序列的后续调用。)Encoding.GetChars will call the fallback for those incomplete sequences, but Decoder will remember those sequences for the next call.)

  • 如果你的应用程序处理字符串输出,则建议使用 GetString 方法。If your app handles string outputs, it is recommended to use the GetString method. 由于此方法必须检查字符串长度并分配一个缓冲区,因此它稍慢一些,但生成的 String 类型是首选的。Since this method must check string length and allocate a buffer, it is slightly slower, but the resulting String type is to be preferred.

  • 的字节版本 GetChars(Byte*, Int32, Char*, Int32) 允许一些快速的方法,尤其是对大缓冲区的多个调用。The byte version of GetChars(Byte*, Int32, Char*, Int32) allows some fast techniques, particularly with multiple calls to large buffers. 但请记住,此方法版本有时不安全,因为指针是必需的。Bear in mind, however, that this method version is sometimes unsafe, since pointers are required.

  • 如果你的应用程序必须转换大量数据,则应重新使用输出缓冲区。If your app must convert a large amount of data, it should reuse the output buffer. 在这种情况下, GetChars(Byte[], Int32, Int32, Char[], Int32) 支持输出字符缓冲区的版本是最佳选择。In this case, the GetChars(Byte[], Int32, Int32, Char[], Int32) version that supports output character buffers is the best choice.

  • 请考虑使用 Decoder.Convert 方法而不是 GetCharCountConsider using the Decoder.Convert method instead of GetCharCount. 转换方法尽可能多地转换数据,如果输出缓冲区太小,则会引发异常。The conversion method converts as much data as possible and throws an exception if the output buffer is too small. 对于流的连续解码,此方法通常是最佳选择。For continuous decoding of a stream, this method is often the best choice.

另请参阅

适用于