UTF7Encoding.GetString(Byte[], Int32, Int32) 方法

定义

命名空间:

System.Text

程序集:

System.Text.Encoding.Extensions.dll

Source:

UTF7Encoding.cs

将字节数组中某个范围的字节解码为一个字符串。

public:
 override System::String ^ GetString(cli::array <System::Byte> ^ bytes, int index, int count);

public override string GetString (byte[] bytes, int index, int count);

override this.GetString : byte[] * int * int -> string

Public Overrides Function GetString (bytes As Byte(), index As Integer, count As Integer) As String

参数

bytes

Byte[]

包含要解码的字节序列的字节数组。

index

Int32

第一个要解码的字节的索引。

count

Int32

要解码的字节数。

返回

String

包含指定字节序列解码结果的 String。

例外

ArgumentNullException

bytes 为 null (Nothing)。

ArgumentOutOfRangeException

index 或 count 小于零。

或

index 和 count 不表示 bytes 中的有效范围。

DecoderFallbackException

(发生回退，有关详细信息，请参阅 .NET) 中的字符编码 。

－和－

将 DecoderFallback 设置为 DecoderExceptionFallback。

示例

下面的代码示例将字符串编码为字节数组，然后将字节解码回字符串。

using namespace System;
using namespace System::Text;
int main()
{
   
   // Create an instance of UTF7Encoding.
   UTF7Encoding^ u7 = gcnew UTF7Encoding( true );
   
   // 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)
   String^ myStr = "za\u0306\u01FD\u03B2";
   
   // Encode the string.
   array<Byte>^myBArr = gcnew array<Byte>(u7->GetByteCount( myStr ));
   u7->GetBytes( myStr, 0, myStr->Length, myBArr, 0 );
   
   // Decode the byte array.
   Console::WriteLine( "The new string is: {0}", u7->GetString( myBArr, 0, myBArr->Length ) );
}

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

The new string is: za??

*/

using System;
using System.Text;

public class SamplesUTF7Encoding  {

   public static void Main()  {

      // Create an instance of UTF7Encoding.
      UTF7Encoding u7 = new UTF7Encoding( true );

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

      // Encode the string.
      byte[] myBArr = new byte[u7.GetByteCount( myStr )];
      u7.GetBytes( myStr, 0, myStr.Length, myBArr, 0 );

      // Decode the byte array.
      Console.WriteLine( "The new string is: {0}", u7.GetString( myBArr, 0, myBArr.Length ) );
   }
}


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

The new string is: za??

*/

Imports System.Text

Public Class SamplesUTF7Encoding

   Public Shared Sub Main()

      ' Create an instance of UTF7Encoding.
      Dim u7 As New UTF7Encoding(True)

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

      ' Encode the string.
      Dim myBArr(u7.GetByteCount(myStr)) As Byte
      u7.GetBytes(myStr, 0, myStr.Length, myBArr, 0)

      ' Decode the byte array.
      Console.WriteLine("The new string is: {0}", u7.GetString(myBArr, 0, myBArr.Length))

   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.
'
'The new string is: za??ß

注解

要转换的数据（例如从流读取的数据）可能仅在顺序块中可用。 在这种情况下，或者，如果数据量太大，需要划分为较小的块，则应用程序应分别使用 Decoder 方法或 Encoder 方法提供的 GetDecoder 或 GetEncoder 。

注意

UTF7Encoding 不提供错误检测。 遇到无效字节时， UTF7Encoding 通常会发出无效字节。 如果字节大于十六进制0x7F，则字节值将零扩展为 Unicode 字符，结果存储在数组中 chars ，任何移位序列都终止。 例如，如果要编码的字节是十六进制0x81，则生成的字符为 U+0081。 出于安全原因，建议应用程序使用 UTF8Encoding、 UnicodeEncoding或 UTF32Encoding 并启用错误检测。

另请参阅

• GetChars(Byte[], Int32, Int32, Char[], Int32)
• GetDecoder()
• GetCharCount(Byte[], Int32, Int32)
• GetMaxCharCount(Int32)