通过

Encoder 类

  • 参考

定义

命名空间:
System.Text
程序集:
System.Text.Encoding.dll
程序集:
System.Runtime.dll
程序集:
mscorlib.dll
程序集:
netstandard.dll
Source:
Encoder.cs
Source:
Encoder.cs
Source:
Encoder.cs

将一组字符转换为一个字节序列。

public ref class Encoder abstract
public abstract class Encoder
[System.Serializable]
public abstract class Encoder
[System.Serializable]
[System.Runtime.InteropServices.ComVisible(true)]
public abstract class Encoder
type Encoder = class
[<System.Serializable>]
type Encoder = class
[<System.Serializable>]
[<System.Runtime.InteropServices.ComVisible(true)>]
type Encoder = class
Public MustInherit Class Encoder
继承
Object
Encoder
属性
SerializableAttribute ComVisibleAttribute

示例

以下示例演示如何使用指定的编码将 Unicode 字符数组转换为字节块。 为了进行比较，字符数组首先使用 UTF7Encoding进行编码。 接下来，使用 对字符数组进行 Encoder编码。

using namespace System;
using namespace System::Text;
using namespace System::Collections;
void ShowArray( Array^ theArray )
{
   IEnumerator^ myEnum = theArray->GetEnumerator();
   while ( myEnum->MoveNext() )
   {
      Object^ o = safe_cast<Object^>(myEnum->Current);
      Console::Write( "[{0}]", o );
   }

   Console::WriteLine( "\n" );
}

int main()
{
   
   // The characters to encode.
   
   // Pi
   // Sigma
   array<Char>^chars = {L'\u03a0',L'\u03a3',L'\u03a6',L'\u03a9'};
   
   // Encode characters using an Encoding Object*.
   Encoding^ encoding = Encoding::UTF7;
   Console::WriteLine( "Using Encoding\n--------------" );
   
   // Encode complete array for comparison.
   array<Byte>^allCharactersFromEncoding = encoding->GetBytes( chars );
   Console::WriteLine( "All characters encoded:" );
   ShowArray( allCharactersFromEncoding );
   
   // Encode characters, one-by-one.
   // The Encoding Object* will NOT maintain state between calls.
   array<Byte>^firstchar = encoding->GetBytes( chars, 0, 1 );
   Console::WriteLine( "First character:" );
   ShowArray( firstchar );
   array<Byte>^secondchar = encoding->GetBytes( chars, 1, 1 );
   Console::WriteLine( "Second character:" );
   ShowArray( secondchar );
   array<Byte>^thirdchar = encoding->GetBytes( chars, 2, 1 );
   Console::WriteLine( "Third character:" );
   ShowArray( thirdchar );
   array<Byte>^fourthchar = encoding->GetBytes( chars, 3, 1 );
   Console::WriteLine( "Fourth character:" );
   ShowArray( fourthchar );
   
   // Now, encode characters using an Encoder Object*.
   Encoder^ encoder = encoding->GetEncoder();
   Console::WriteLine( "Using Encoder\n-------------" );
   
   // Encode complete array for comparison.
   array<Byte>^allCharactersFromEncoder = gcnew array<Byte>(encoder->GetByteCount( chars, 0, chars->Length, true ));
   encoder->GetBytes( chars, 0, chars->Length, allCharactersFromEncoder, 0, true );
   Console::WriteLine( "All characters encoded:" );
   ShowArray( allCharactersFromEncoder );
   
   // Do not flush state; i.e. maintain state between calls.
   bool bFlushState = false;
   
   // Encode characters one-by-one.
   // By maintaining state, the Encoder will not store extra bytes in the output.
   array<Byte>^firstcharNoFlush = gcnew array<Byte>(encoder->GetByteCount( chars, 0, 1, bFlushState ));
   encoder->GetBytes( chars, 0, 1, firstcharNoFlush, 0, bFlushState );
   Console::WriteLine( "First character:" );
   ShowArray( firstcharNoFlush );
   array<Byte>^secondcharNoFlush = gcnew array<Byte>(encoder->GetByteCount( chars, 1, 1, bFlushState ));
   encoder->GetBytes( chars, 1, 1, secondcharNoFlush, 0, bFlushState );
   Console::WriteLine( "Second character:" );
   ShowArray( secondcharNoFlush );
   array<Byte>^thirdcharNoFlush = gcnew array<Byte>(encoder->GetByteCount( chars, 2, 1, bFlushState ));
   encoder->GetBytes( chars, 2, 1, thirdcharNoFlush, 0, bFlushState );
   Console::WriteLine( "Third character:" );
   ShowArray( thirdcharNoFlush );
   
   // Must flush state on last call to GetBytes().
   bFlushState = true;
   array<Byte>^fourthcharNoFlush = gcnew array<Byte>(encoder->GetByteCount( chars, 3, 1, bFlushState ));
   encoder->GetBytes( chars, 3, 1, fourthcharNoFlush, 0, bFlushState );
   Console::WriteLine( "Fourth character:" );
   ShowArray( fourthcharNoFlush );
}

/* This code example produces the following output.

Using Encoding
--------------
All characters encoded:
[43][65][54][65][68][111][119][79][109][65][54][107][45]

First character:
[43][65][54][65][45]

Second character:
[43][65][54][77][45]

Third character:
[43][65][54][89][45]

Fourth character:
[43][65][54][107][45]

Using Encoder
-------------
All characters encoded:
[43][65][54][65][68][111][119][79][109][65][54][107][45]

First character:
[43][65][54]

Second character:
[65][68][111]

Third character:
[119][79][109]

Fourth character:
[65][54][107][45]


*/

using System;
using System.Text;

class EncoderTest {
    public static void Main() {
        // The characters to encode.
        Char[] chars = new Char[] {
            '\u0023', // #
            '\u0025', // %
            '\u03a0', // Pi
            '\u03a3'  // Sigma
        };

        // Encode characters using an Encoding object.
        Encoding encoding = Encoding.UTF7;
        Console.WriteLine("Using Encoding\n--------------");

        // Encode complete array for comparison.
        Byte[] allCharactersFromEncoding = encoding.GetBytes(chars);
        Console.WriteLine("All characters encoded:");
        ShowArray(allCharactersFromEncoding);

        // Encode characters, one-by-one.
        // The Encoding object will NOT maintain state between calls.
        Byte[] firstchar = encoding.GetBytes(chars, 0, 1);
        Console.WriteLine("First character:");
        ShowArray(firstchar);

        Byte[] secondchar = encoding.GetBytes(chars, 1, 1);
        Console.WriteLine("Second character:");
        ShowArray(secondchar);

        Byte[] thirdchar = encoding.GetBytes(chars, 2, 1);
        Console.WriteLine("Third character:");
        ShowArray(thirdchar);

        Byte[] fourthchar = encoding.GetBytes(chars, 3, 1);
        Console.WriteLine("Fourth character:");
        ShowArray(fourthchar);

        // Now, encode characters using an Encoder object.
        Encoder encoder = encoding.GetEncoder();
        Console.WriteLine("Using Encoder\n-------------");

        // Encode complete array for comparison.
        Byte[] allCharactersFromEncoder = new Byte[encoder.GetByteCount(chars, 0, chars.Length, true)];
        encoder.GetBytes(chars, 0, chars.Length, allCharactersFromEncoder, 0, true);
        Console.WriteLine("All characters encoded:");
        ShowArray(allCharactersFromEncoder);

        // Do not flush state; i.e. maintain state between calls.
        bool bFlushState = false;

        // Encode characters one-by-one.
        // By maintaining state, the Encoder will not store extra bytes in the output.
        Byte[] firstcharNoFlush = new Byte[encoder.GetByteCount(chars, 0, 1, bFlushState)];
        encoder.GetBytes(chars, 0, 1, firstcharNoFlush, 0, bFlushState);
        Console.WriteLine("First character:");
        ShowArray(firstcharNoFlush);

        Byte[] secondcharNoFlush = new Byte[encoder.GetByteCount(chars, 1, 1, bFlushState)];
        encoder.GetBytes(chars, 1, 1, secondcharNoFlush, 0, bFlushState);
        Console.WriteLine("Second character:");
        ShowArray(secondcharNoFlush);

        Byte[] thirdcharNoFlush = new Byte[encoder.GetByteCount(chars, 2, 1, bFlushState)];
        encoder.GetBytes(chars, 2, 1, thirdcharNoFlush, 0, bFlushState);
        Console.WriteLine("Third character:");
        ShowArray(thirdcharNoFlush);

        // Must flush state on last call to GetBytes().
        bFlushState = true;
        
        Byte[] fourthcharNoFlush = new Byte[encoder.GetByteCount(chars, 3, 1, bFlushState)];
        encoder.GetBytes(chars, 3, 1, fourthcharNoFlush, 0, bFlushState);
        Console.WriteLine("Fourth character:");
        ShowArray(fourthcharNoFlush);
    }

    public static void ShowArray(Array theArray) {
        foreach (Object o in theArray) {
            Console.Write("[{0}]", o);
        }
        Console.WriteLine("\n");
    }
}

/* This code example produces the following output.

Using Encoding
--------------
All characters encoded:
[43][65][67][77][65][74][81][79][103][65][54][77][45]

First character:
[43][65][67][77][45]

Second character:
[43][65][67][85][45]

Third character:
[43][65][54][65][45]

Fourth character:
[43][65][54][77][45]

Using Encoder
-------------
All characters encoded:
[43][65][67][77][65][74][81][79][103][65][54][77][45]

First character:
[43][65][67]

Second character:
[77][65][74]

Third character:
[81][79][103]

Fourth character:
[65][54][77][45]


*/

Imports System.Text
Imports Microsoft.VisualBasic.Strings

Class EncoderTest
    
    Public Shared Sub Main()
        ' Unicode characters.
        ' ChrW(35)  = #
        ' ChrW(37)  = %
        ' ChrW(928) = Pi
        ' ChrW(931) = Sigma
        Dim chars() As Char = {ChrW(35), ChrW(37), ChrW(928), ChrW(931)}
        
        ' Encode characters using an Encoding object.
        Dim encoding As Encoding = Encoding.UTF7
        Console.WriteLine( _
            "Using Encoding" & _
            ControlChars.NewLine & _
            "--------------" _
        )
        
        ' Encode complete array for comparison.
        Dim allCharactersFromEncoding As Byte() = encoding.GetBytes(chars)
        Console.WriteLine("All characters encoded:")
        ShowArray(allCharactersFromEncoding)
        
        ' Encode characters, one-by-one.
        ' The Encoding object will NOT maintain state between calls.
        Dim firstchar As Byte() = encoding.GetBytes(chars, 0, 1)
        Console.WriteLine("First character:")
        ShowArray(firstchar)
        
        Dim secondchar As Byte() = encoding.GetBytes(chars, 1, 1)
        Console.WriteLine("Second character:")
        ShowArray(secondchar)
        
        Dim thirdchar As Byte() = encoding.GetBytes(chars, 2, 1)
        Console.WriteLine("Third character:")
        ShowArray(thirdchar)
        
        Dim fourthchar As Byte() = encoding.GetBytes(chars, 3, 1)
        Console.WriteLine("Fourth character:")
        ShowArray(fourthchar)
        
        
        ' Now, encode characters using an Encoder object.
        Dim encoder As Encoder = encoding.GetEncoder()
        Console.WriteLine( _
            "Using Encoder" & _
            ControlChars.NewLine & _
            "-------------" _
        )
        
        ' Encode complete array for comparison.
        Dim allCharactersFromEncoder( _
            encoder.GetByteCount(chars, 0, chars.Length, True) _
        ) As Byte
        encoder.GetBytes(chars, 0, chars.Length, allCharactersFromEncoder, 0, True)
        Console.WriteLine("All characters encoded:")
        ShowArray(allCharactersFromEncoder)
        
        ' Do not flush state; i.e. maintain state between calls.
        Dim bFlushState As Boolean = False
        
        ' Encode characters one-by-one.
        ' By maintaining state, the Encoder will not store extra bytes in the output.
        Dim firstcharNoFlush( _
            encoder.GetByteCount(chars, 0, 1, bFlushState) _
        ) As Byte
        encoder.GetBytes(chars, 0, 1, firstcharNoFlush, 0, bFlushState)
        Console.WriteLine("First character:")
        ShowArray(firstcharNoFlush)
        
        Dim secondcharNoFlush( _
            encoder.GetByteCount(chars, 1, 1, bFlushState) _
        ) As Byte
        encoder.GetBytes(chars, 1, 1, secondcharNoFlush, 0, bFlushState)
        Console.WriteLine("Second character:")
        ShowArray(secondcharNoFlush)
        
        Dim thirdcharNoFlush( _
            encoder.GetByteCount(chars, 2, 1, bFlushState) _
        ) As Byte
        encoder.GetBytes(chars, 2, 1, thirdcharNoFlush, 0, bFlushState)
        Console.WriteLine("Third character:")
        ShowArray(thirdcharNoFlush)
        
        ' Must flush state on last call to GetBytes().
        bFlushState = True
        
        Dim fourthcharNoFlush( _
            encoder.GetByteCount(chars, 3, 1, bFlushState) _
        ) As Byte
        encoder.GetBytes(chars, 3, 1, fourthcharNoFlush, 0, bFlushState)
        Console.WriteLine("Fourth character:")
        ShowArray(fourthcharNoFlush)
    End Sub
    
    
    Public Shared Sub ShowArray(theArray As Array)
        Dim o As Object
        For Each o In  theArray
            Console.Write("[{0}]", o)
        Next o
        Console.WriteLine(ControlChars.NewLine)
    End Sub
End Class

'This code example produces the following output.
'
'Using Encoding
'--------------
'All characters encoded:
'[43][65][67][77][65][74][81][79][103][65][54][77][45]
'
'First character:
'[43][65][67][77][45]
'
'Second character:
'[43][65][67][85][45]
'
'Third character:
'[43][65][54][65][45]
'
'Fourth character:
'[43][65][54][77][45]
'
'Using Encoder
'-------------
'All characters encoded:
'[43][65][67][77][65][74][81][79][103][65][54][77][45][0]
'
'First character:
'[43][65][67][0]
'
'Second character:
'[77][65][74][0]
'
'Third character:
'[81][79][103][0]
'
'Fourth character:
'[65][54][77][45][0]
'

注解

若要获取 类实现的 Encoder 实例，应用程序应使用 GetEncoder 实现的 Encoding 方法。

GetByteCount方法确定导致对一组 Unicode 字符进行编码的字节数， GetBytes 方法执行实际编码。 类中提供了这两种方法的 Encoder 多个版本。 有关详细信息，请参阅 Encoding.GetBytes。

Encoder对象维护对 GetBytes 或 Convert 方法的连续调用之间的状态信息，以便它可以正确编码跨块的字符序列。 Encoder还保留数据块末尾的尾随字符，并在下一编码操作中使用尾随字符。 例如，数据块可能以不匹配的高代理项结束，并且匹配的低代理项可能位于下一个数据块中。 因此， GetDecoder 和 GetEncoder 对于网络传输和文件操作非常有用，因为这些操作经常处理数据块而不是完整的数据流。

注意

当应用程序完成数据流时，它应确保在适当的方法调用中将 参数设置为 flush 来 true 刷新状态信息。 如果发生异常或应用程序切换流，则应调用 Reset 以清除对象的内部状态 Encoder 。

实施者说明

当应用程序从此类继承时，它必须重写所有成员。

构造函数

Encoder()

初始化 Encoder 类的新实例。

属性

Fallback

获取或设置当前 EncoderFallback 对象的 Encoder 对象。
FallbackBuffer

获取与当前 EncoderFallbackBuffer 对象关联的 Encoder 对象。

方法

Convert(Char*, Int32, Byte*, Int32, Boolean, Int32, Int32, Boolean)

将 Unicode 字符的缓冲区转换为编码的字节序列，并将结果存储在另一个缓冲区中。
Convert(Char[], Int32, Int32, Byte[], Int32, Int32, Boolean, Int32, Int32, Boolean)

将 Unicode 字符的数组转换为编码字节序列，并将结果存储在字节数组中。
Convert(ReadOnlySpan<Char>, Span<Byte>, Boolean, Int32, Int32, Boolean)

将 Unicode 字符的范围转换为编码的字节序列，并将结果存储在另一个缓冲区中。
Equals(Object)

确定指定对象是否等于当前对象。

(继承自 Object)
GetByteCount(Char*, Int32, Boolean)

在派生类中重写时，计算对一组字符（从指定的字符指针处开始）进行编码所产生的字节数。 一个参数指示计算后是否要清除编码器的内部状态。
GetByteCount(Char[], Int32, Int32, Boolean)

在派生类中重写时，计算对指定字符数组中的一组字符进行编码所产生的字节数。 一个参数指示计算后是否要清除编码器的内部状态。
GetByteCount(ReadOnlySpan<Char>, Boolean)

在派生类中重写时，计算对“字符”范围中的一组字符进行编码所产生的字节数。 一个参数指示计算后是否要清除编码器的内部状态。
GetBytes(Char*, Int32, Byte*, Int32, Boolean)

在派生类中重写时，将一组字符（从指定的字符指针处开始）和内部缓冲区中的任何字符编码为从指定字节指针开始存储的字节序列。 一个参数指示转换后是否清除编码器的内部状态。
GetBytes(Char[], Int32, Int32, Byte[], Int32, Boolean)

在派生类中重写时，将指定字符数组中的一组字符和内部缓冲区中的任何字符编码到指定的字节数组中。 一个参数指示转换后是否清除编码器的内部状态。
GetBytes(ReadOnlySpan<Char>, Span<Byte>, Boolean)

在派生类中重写时，将输入字符范围内的一组字符和内部缓冲区中的所有字符编码为存储在输入字节范围中的字节序列。 一个参数指示转换后是否清除编码器的内部状态。
GetHashCode()

作为默认哈希函数。

(继承自 Object)
GetType()

获取当前实例的 Type。

(继承自 Object)
MemberwiseClone()

创建当前 Object 的浅表副本。

(继承自 Object)
Reset()

在派生类中重写时，将编码器设置回它的初始状态。
ToString()

返回表示当前对象的字符串。

(继承自 Object)

扩展方法

Convert(Encoder, ReadOnlySequence<Char>, IBufferWriter<Byte>, Boolean, Int64, Boolean)

将 ReadOnlySequence<T> 转换为已编码的字节，并将结果写入 writer。
Convert(Encoder, ReadOnlySpan<Char>, IBufferWriter<Byte>, Boolean, Int64, Boolean)

使用 encoder 将 ReadOnlySpan<T> 转换为字节，并将结果写入 writer。

适用于

另请参阅