UnicodeEncoding 建構函式

參考

定義

命名空間:: System.Text

組件:: System.Text.Encoding.Extensions.dll

組件:: mscorlib.dll

組件:: netstandard.dll

重要

部分資訊涉及發行前產品，在發行之前可能會有大幅修改。 Microsoft 對此處提供的資訊，不做任何明確或隱含的瑕疵擔保。

初始化 UnicodeEncoding 類別的新執行個體。

多載

UnicodeEncoding()	初始化 UnicodeEncoding 類別的新執行個體。
UnicodeEncoding(Boolean, Boolean)	初始化 UnicodeEncoding 類別的新執行個體。參數會指定是否使用位元組由大到小的位元組順序，以及 GetPreamble() 方法是否傳回 Unicode 位元組順序標記。
UnicodeEncoding(Boolean, Boolean, Boolean)	初始化 UnicodeEncoding 類別的新執行個體。參數會指定是否使用位元組由大到小的位元組順序、是否提供 Unicode 位元組順序標記，以及是否在偵測到無效的編碼方式時擲回例外狀況。

UnicodeEncoding()

初始化 UnicodeEncoding 類別的新執行個體。

public:
 UnicodeEncoding();

public UnicodeEncoding ();

Public Sub New ()

範例

下列範例示範如何建立新的 UnicodeEncoding 實例，並顯示編碼的名稱。

using namespace System;
using namespace System::Text;
int main()
{
   UnicodeEncoding^ unicode = gcnew UnicodeEncoding;
   String^ encodingName = unicode->EncodingName;
   Console::WriteLine( "Encoding name: {0}", encodingName );
}

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

備註

這個建構函式會建立使用小尾位元組順序的實例、提供 Unicode 位元組順序標記，而且在偵測到無效編碼時不會擲回例外狀況。

警告

基於安全性考慮，您應該呼叫建構函式並將其 UnicodeEncoding(Boolean, Boolean, Boolean) 引數設定 throwOnInvalidBytes 為 true 來啟用錯誤偵測。

適用於

UnicodeEncoding(Boolean, Boolean)

初始化 UnicodeEncoding 類別的新執行個體。參數會指定是否使用位元組由大到小的位元組順序，以及 GetPreamble() 方法是否傳回 Unicode 位元組順序標記。

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)

參數

bigEndian: Boolean

true 表示要使用位元組由大到小的位元組順序 (最大顯著性位元組在前)，false 表示要使用位元組由小到大的位元組順序 (最小顯著性位元組在前)。

byteOrderMark: Boolean

true 指定 GetPreamble() 方法會傳回 Unicode 位元組順序標記；否則為 false。

範例

下列範例示範如何建立新的 UnicodeEncoding 實例，指定是否支援小端或大位元組位元組順序和 Unicode 位元組順序標記。

using namespace System;
using namespace System::Text;
void DescribeEquivalence( Boolean isEquivalent )
{
   Console::WriteLine( " {0} equivalent encoding.", (isEquivalent ? (String^)"An" : "Not an") );
}

int main()
{
   
   // Create a UnicodeEncoding without parameters.
   UnicodeEncoding^ unicode = gcnew UnicodeEncoding;
   
   // Create a UnicodeEncoding to support little-endian Byte ordering
   // and include the Unicode Byte order mark.
   UnicodeEncoding^ unicodeLittleEndianBOM = gcnew 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 = gcnew 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 = gcnew 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 = gcnew UnicodeEncoding( true,false );
   
   // Compare this UnicodeEncoding to the UnicodeEncoding without parameters.
   DescribeEquivalence( unicode->Equals( unicodeBigEndianNoBOM ) );
}

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

備註

這個建構函式會建立一個實例，在偵測到不正確編碼時不會擲回例外狀況。

警告

基於安全性考慮，您應該呼叫建構函式並將其 UnicodeEncoding(Boolean, Boolean, Boolean) 引數設定 throwOnInvalidBytes 為 true 來啟用錯誤偵測。

參數 byteOrderMark 會控制方法的 GetPreamble 作業。如果 true 為，則方法會傳回位元組陣列，其中包含 UTF-16 格式的 Unicode 位元組順序標記 (BOM) 。如果 false 為，則會傳回長度為零的位元組陣列。不過，設定 byteOrderMark 為不會讓 GetBytes 方法在位元組陣列開頭加上 BOM，也不會使 GetByteCount 方法在位元組計數中包含 BOM true 中的位元組數目。

另請參閱

GetPreamble()

適用於

UnicodeEncoding(Boolean, Boolean, Boolean)

初始化 UnicodeEncoding 類別的新執行個體。參數會指定是否使用位元組由大到小的位元組順序、是否提供 Unicode 位元組順序標記，以及是否在偵測到無效的編碼方式時擲回例外狀況。

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)

參數

bigEndian: Boolean

true 表示要使用位元組由大到小的位元組順序 (最大顯著性位元組在前)，false 表示要使用位元組由小到大的位元組順序 (最小顯著性位元組在前)。

byteOrderMark: Boolean

true 指定 GetPreamble() 方法會傳回 Unicode 位元組順序標記；否則為 false。

throwOnInvalidBytes: Boolean

true，可指定在偵測到無效的編碼方式時應擲回一個例外狀況，否則為 false。

範例

下列範例示範 UnicodeEncoding 的行為，兩者皆已啟用錯誤偵測，且不含。

using namespace System;
using namespace System::Text;
void PrintDecodedString( array<Byte>^bytes, Encoding^ enc );
int main()
{
   
   // Create an instance of UnicodeEncoding using little-endian byte order.
   // This will be used for encoding.
   UnicodeEncoding^ u16LE = gcnew 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 = gcnew UnicodeEncoding( true,true,true );
   UnicodeEncoding^ u16noED = gcnew 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.
   array<Byte>^myBytes = gcnew array<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.
void PrintDecodedString( array<Byte>^bytes, Encoding^ enc )
{
   try
   {
      Console::WriteLine( "   Decoded string: {0}", enc->GetString( bytes, 0, bytes->Length ) );
   }
   catch ( System::ArgumentException^ e ) 
   {
      Console::WriteLine( e );
   }

   Console::WriteLine();
}

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

備註

throwOnInvalidBytes如果參數為 true ，則偵測無效位元組序列的方法會 System.ArgumentException 擲回。否則，方法不會擲回例外狀況，而且會忽略不正確序列。

警告

基於安全性考慮，您應該使用此建構函式來建立類別的 UnicodeEncoding 實例，並將設定 throwOnInvalidBytes 為 true 來開啟錯誤偵測。

另請參閱

GetPreamble()

適用於

共用方式為

UnicodeEncoding 建構函式

定義

多載

UnicodeEncoding()

範例

備註

適用於

UnicodeEncoding(Boolean, Boolean)

參數

範例

備註

另請參閱

適用於

UnicodeEncoding(Boolean, Boolean, Boolean)

參數

範例

備註

另請參閱

適用於

其他資源