Encoder 类

定义

命名空间:: System.Text

程序集:: mscorlib.dll, System.Text.Encoding.dll

程序集:: netstandard.dll, System.Runtime.dll

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

Source:: Encoder.cs

Source:: Encoder.cs

重要

一些信息与预发行产品相关，相应产品在发行之前可能会进行重大修改。对于此处提供的信息，Microsoft 不作任何明示或暗示的担保。

将一组字符转换为字节序列。

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。接下来，使用 .Encoder

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 实现的方法 Encoding 。

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

对象 Encoder 在连续调用 GetBytes 或 Convert 方法之间维护状态信息，以便它可以正确编码跨块的字符序列。它还 Encoder 保留数据块末尾的尾随字符，并在下一个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尾，匹配的低代理项可能位于下一个数据块中。因此， GetDecoder 对于 GetEncoder 网络传输和文件操作非常有用，因为这些操作通常处理数据块而不是完整的数据流。

注释

当应用程序使用数据流完成时，应通过在适当的方法调用中将参数设置为flushtrue确保刷新状态信息。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

名称	说明
Encoder()	初始化 Encoder 类的新实例。

属性

名称	说明
Fallback	获取或设置 EncoderFallback 当前 Encoder 对象的对象。
FallbackBuffer	EncoderFallbackBuffer获取与当前Encoder对象关联的对象。

方法

名称	说明
Convert(Char[], Int32, Int32, Byte[], Int32, Int32, Boolean, Int32, Int32, Boolean)	将 Unicode 字符数组转换为编码的字节序列，并将结果存储在字节数组中。
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(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)	确定指定的对象是否等于当前对象。 (继承自 Object)
GetByteCount(Char[], Int32, Int32, Boolean)	在派生类中重写时，计算通过编码指定字符数组中的一组字符生成的字节数。参数指示是否在计算后清除编码器的内部状态。
GetByteCount(Char*, Int32, Boolean)	在派生类中重写时，计算通过编码一组字符（从指定字符指针开始）生成的字节数。参数指示是否在计算后清除编码器的内部状态。
GetByteCount(ReadOnlySpan<Char>, Boolean)	在派生类中重写时，计算通过编码“chars”范围中的一组字符生成的字节数。参数指示是否在计算后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为指定的字节数组。参数指示是否在转换后清除编码器的内部状态。
GetBytes(Char, Int32, Byte, Int32, Boolean)	在派生类中重写时，将一组从指定字符指针开始的字符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。参数指示是否在转换后清除编码器的内部状态。
GetBytes(ReadOnlySpan<Char>, Span<Byte>, Boolean)	在派生类中重写时，将输入字符范围中的一组字符和内部缓冲区中的任何字符编码为存储在输入字节范围中的字节序列。参数指示是否在转换后清除编码器的内部状态。
GetHashCode()	用作默认哈希函数。 (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，将编码器设置回其初始状态。
ToString()	返回一个表示当前对象的字符串。 (继承自 Object)

扩展方法

名称	说明
Convert(Encoder, ReadOnlySequence<Char>, IBufferWriter<Byte>, Boolean, Int64, Boolean)	将 a ReadOnlySequence<T> 转换为编码的字节并将结果写入到 `writer`.
Convert(Encoder, ReadOnlySpan<Char>, IBufferWriter<Byte>, Boolean, Int64, Boolean)	将结果 ReadOnlySpan<T> 转换为字节， `encoder` 并将结果 `writer`写入到。

适用于

另请参阅

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