UnicodeEncoding 构造函数

定义

命名空间:: System.Text

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

程序集:: netstandard.dll, System.Text.Encoding.Extensions.dll

程序集:: System.Text.Encoding.Extensions.dll

程序集:: mscorlib.dll

程序集:: netstandard.dll

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。

初始化 UnicodeEncoding 类的新实例。

重载

名称	说明
UnicodeEncoding()	初始化 UnicodeEncoding 类的新实例。
UnicodeEncoding(Boolean, Boolean)	初始化 UnicodeEncoding 类的新实例。参数指定是否使用大字节字节顺序，以及该方法是否 GetPreamble() 返回 Unicode 字节顺序标记。
UnicodeEncoding(Boolean, Boolean, Boolean)	初始化 UnicodeEncoding 类的新实例。参数指定是否使用大字节字节顺序、是否提供 Unicode 字节顺序标记，以及是否在检测到无效编码时引发异常。

UnicodeEncoding()

Source:: UnicodeEncoding.cs

Source:: UnicodeEncoding.cs

Source:: UnicodeEncoding.cs

Source:: UnicodeEncoding.cs

Source:: UnicodeEncoding.cs

初始化 UnicodeEncoding 类的新实例。

public:
 UnicodeEncoding();

public UnicodeEncoding();

Public Sub New ()

示例

以下示例演示如何创建新 UnicodeEncoding 实例并显示编码的名称。

using System;
using System.Text;

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

Imports System.Text

Class UnicodeEncodingExample

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

注解

此构造函数创建一个实例，该实例使用小字节字节顺序，提供 Unicode 字节顺序标记，并在检测到无效编码时不引发异常。

Caution

出于安全原因，应通过调用构造函数并将其参数设置为 <a0/> 来启用错误检测。

适用于

UnicodeEncoding(Boolean, Boolean)

Source:: UnicodeEncoding.cs

Source:: UnicodeEncoding.cs

Source:: UnicodeEncoding.cs

Source:: UnicodeEncoding.cs

Source:: UnicodeEncoding.cs

初始化 UnicodeEncoding 类的新实例。参数指定是否使用大字节字节顺序，以及该方法是否 GetPreamble() 返回 Unicode 字节顺序标记。

public:
 UnicodeEncoding(bool bigEndian, bool byteOrderMark);

public UnicodeEncoding(bool bigEndian, bool byteOrderMark);

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

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

参数

bigEndian: Boolean

true 使用大字节字节顺序（最重要字节第一），或使用 false 小字节字节顺序（最不重要的字节优先）。

byteOrderMark: Boolean

如果指定该方法返回 Unicode 字节顺序标记，则为 /&;。

示例

下面的示例演示如何创建一个新 UnicodeEncoding 实例，该实例指定是支持小 endian 还是大字节字节排序以及 Unicode 字节顺序标记。

using System;
using System.Text;

class UnicodeEncodingExample {
    public static void Main() {

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

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

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

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

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

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

Imports System.Text

Class UnicodeEncodingExample
    
    Public Shared Sub Main()

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

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

注解

此构造函数创建一个实例，该实例在检测到无效编码时不会引发异常。

Caution

出于安全原因，应通过调用构造函数并将其参数设置为 <a0/> 来启用错误检测。

参数 byteOrderMark 控制方法的操作 GetPreamble 。如果 true，该方法返回一个字节数组，其中包含 UTF-16 格式的 Unicode 字节顺序标记（BOM）。如果 false返回零长度字节数组。但是，设置为byteOrderMarktrue不会导致GetBytes方法在字节数组的开头为 BOM 添加前缀，也不会导致GetByteCount该方法在字节计数中包含 BOM 中的字节数。

另请参阅

GetPreamble()

适用于

UnicodeEncoding(Boolean, Boolean, Boolean)

Source:: UnicodeEncoding.cs

Source:: UnicodeEncoding.cs

Source:: UnicodeEncoding.cs

Source:: UnicodeEncoding.cs

Source:: UnicodeEncoding.cs

初始化 UnicodeEncoding 类的新实例。参数指定是否使用大字节字节顺序、是否提供 Unicode 字节顺序标记，以及是否在检测到无效编码时引发异常。

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

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

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

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

参数

bigEndian: Boolean

true 使用大字节字节顺序（首先最重要的字节）： false 使用小字节字节顺序（第一个最小有效字节）。

byteOrderMark: Boolean

如果指定该方法返回 Unicode 字节顺序标记，则为 /&;。

throwOnInvalidBytes: Boolean

true 指定在检测到无效编码时应引发异常;否则，为 false.

示例

以下示例演示了启用和未启用错误检测的行为 UnicodeEncoding。

using System;
using System.Text;

public class SamplesUnicodeEncoding  {

   public static void Main()  {

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

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

      // Create byte arrays from the same string containing the following characters:
      //    Latin Small Letter Z (U+007A)
      //    Latin Small Letter A (U+0061)
      //    Combining Breve (U+0306)
      //    Latin Small Letter AE With Acute (U+01FD)
      //    Greek Small Letter Beta (U+03B2)
      //    Latin Capital Letter U with  Diaeresis (U+00DC)
      String myStr = "za\u0306\u01FD\u03B2\u00DC";

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

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

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

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

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

      Console.WriteLine();
   }
}

Imports System.Text

Public Class SamplesUnicodeEncoding   

   Public Shared Sub Main()

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

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

      ' Create byte arrays from the same string containing the following characters:
      '    Latin Small Letter Z (U+007A)
      '    Latin Small Letter A (U+0061)
      '    Combining Breve (U+0306)
      '    Latin Small Letter AE With Acute (U+01FD)
      '    Greek Small Letter Beta (U+03B2)
      '    Latin Capital Letter U with  Diaeresis (U+00DC)
      Dim myStr As String = "za" & ChrW(&H0306) & ChrW(&H01FD) & ChrW(&H03B2) & ChrW(&H00DC)

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

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

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

   End Sub


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

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

      Console.WriteLine()

   End Sub

End Class

注解

如果参数 throwOnInvalidBytes 是 true，则检测无效字节序列的方法将 System.ArgumentException引发。否则，该方法不会引发异常，并且忽略无效序列。

Caution

出于安全原因，应使用此构造函数创建类的实例，并通过设置为 <a0/> 来启用错误检测。

另请参阅

GetPreamble()

适用于

反馈

此页面是否有帮助？