BinaryReader.ReadChars(Int32) 方法

定義

命名空間:

System.IO

組件:

System.Runtime.dll

來源:

BinaryReader.cs

讀取目前資料流中的指定字元數，並將資料傳入字元陣列中，然後依據使用的 Encoding 以及正在從資料流中讀取的指定字元，前移目前的位置。

public:
 virtual cli::array <char> ^ ReadChars(int count);

public virtual char[] ReadChars (int count);

abstract member ReadChars : int -> char[]
override this.ReadChars : int -> char[]

Public Overridable Function ReadChars (count As Integer) As Char()

參數

count

Int32

要讀取的字元數。

傳回

Char[]

字元陣列，含有從基礎資料流讀取的資料。 如果已到達資料流末端，這可能會小於要求的字元數。

例外狀況

ArgumentException

欲讀取的解碼字元數大於 count。 如果 Unicode 解碼器傳回後援字元或 Surrogate 組，就會發生這個情況。

ObjectDisposedException

資料流已關閉。

IOException

發生 I/O 錯誤。

ArgumentOutOfRangeException

count 為負。

範例

下列程式代碼範例示範如何使用記憶體作為備份儲存區來讀取和寫入數據。

using namespace System;
using namespace System::IO;
int main()
{
   array<Char>^invalidPathChars = Path::InvalidPathChars;
   MemoryStream^ memStream = gcnew MemoryStream;
   BinaryWriter^ binWriter = gcnew BinaryWriter( memStream );
   
   // Write to memory.
   binWriter->Write( "Invalid file path characters are: " );
   binWriter->Write( Path::InvalidPathChars );
   
   // Create the reader using the same MemoryStream 
   // as used with the writer.
   BinaryReader^ binReader = gcnew BinaryReader( memStream );
   
   // Set Position to the beginning of the stream.
   binReader->BaseStream->Position = 0;
   
   // Read the data from memory and write it to the console.
   Console::Write( binReader->ReadString() );
   Console::WriteLine( binReader->ReadChars( (int)(memStream->Length - memStream->Position) ) );
}

using System;
using System.IO;

class BinaryRW
{
    static void Main()
    {
        char[] invalidPathChars = Path.InvalidPathChars;
        MemoryStream memStream = new MemoryStream();
        BinaryWriter binWriter = new BinaryWriter(memStream);

        // Write to memory.
        binWriter.Write("Invalid file path characters are: ");
        binWriter.Write(Path.InvalidPathChars);

        // Create the reader using the same MemoryStream
        // as used with the writer.
        BinaryReader binReader = new BinaryReader(memStream);

        // Set Position to the beginning of the stream.
        memStream.Position = 0;

        // Read the data from memory and write it to the console.
        Console.Write(binReader.ReadString());
        Console.WriteLine(binReader.ReadChars(
            (int)(memStream.Length - memStream.Position)));
    }
}

open System.IO

let invalidPathChars = Path.GetInvalidPathChars()
let memStream = new MemoryStream()
let binWriter = new BinaryWriter(memStream)

// Write to memory.
binWriter.Write "Invalid file path characters are: "
binWriter.Write invalidPathChars

// Create the reader using the same MemoryStream
// as used with the writer.
let binReader = new BinaryReader(memStream)

// Set Position to the beginning of the stream.
memStream.Position <- 0

// Read the data from memory and write it to the console.
printf $"{binReader.ReadString()}"
printfn $"{binReader.ReadChars(int (memStream.Length - memStream.Position))}"

Imports System.IO

Public Class BinaryRW

    Shared Sub Main()
    
        Dim invalidPathChars() As Char = Path.InvalidPathChars
        Dim memStream As new MemoryStream()
        Dim binWriter As New BinaryWriter(memStream)

        ' Write to memory.
        binWriter.Write("Invalid file path characters are: ")
        binWriter.Write(Path.InvalidPathChars)

        ' Create the reader using the same MemoryStream 
        ' as used with the writer.
        Dim binReader As New BinaryReader(memStream)

        ' Set Position to the beginning of the stream.
        memStream.Position = 0

        ' Read the data from memory and write it to the console.
        Console.Write(binReader.ReadString())
        Console.WriteLine(binReader.ReadChars( _
            CInt(memStream.Length - memStream.Position)))
    
    End Sub
End Class

備註

BinaryReader 不會在失敗的讀取作業之後還原檔案位置。

從網路串流讀取時，在某些情況下， ReadChars 如果 BinaryReader 是以 Unicode 編碼建構，方法可能會從數據流讀取額外的字元。 如果發生這種情況，您可以使用 ReadBytes 方法來讀取固定長度的位元組陣列，然後將該數位傳遞至 ReadChars 方法。

另請參閱

• Encoding
• 檔案和資料流 I/O
• 作法：讀取檔案中的文字
• 作法：將文字寫入檔案