BinaryReader.ReadByte Méthode

Définition

Espace de noms:

System.IO

Assembly:

System.Runtime.dll

Source:

BinaryReader.cs

Lit l'octet suivant du flux actuel et avance la position actuelle du flux d'un octet.

public:
 virtual System::Byte ReadByte();

public virtual byte ReadByte ();

abstract member ReadByte : unit -> byte
override this.ReadByte : unit -> byte

Public Overridable Function ReadByte () As Byte

Retours

Byte

Octet suivant lu dans le flux actuel.

Exceptions

EndOfStreamException

La fin du flux est atteinte.

ObjectDisposedException

Le flux est fermé.

IOException

Une erreur d'E/S s'est produite.

Exemples

L’exemple de code suivant montre comment écrire des données binaires à l’aide de la mémoire comme magasin de stockage, puis vérifier que les données ont été écrites correctement.

using namespace System;
using namespace System::IO;
int main()
{
   int i = 0;
   
   // Create random data to write to the stream.
   array<Byte>^writeArray = gcnew array<Byte>(1000);
   (gcnew Random)->NextBytes( writeArray );
   BinaryWriter^ binWriter = gcnew BinaryWriter( gcnew MemoryStream );
   BinaryReader^ binReader = gcnew BinaryReader( binWriter->BaseStream );
   try
   {
      
      // Write the data to the stream.
      Console::WriteLine( "Writing the data." );
      for ( i = 0; i < writeArray->Length; i++ )
      {
         binWriter->Write( writeArray[ i ] );

      }
      
      // Set the stream position to the beginning of the stream.
      binReader->BaseStream->Position = 0;
      
      // Read and verify the data from the stream.
      for ( i = 0; i < writeArray->Length; i++ )
      {
         if ( binReader->ReadByte() != writeArray[ i ] )
         {
            Console::WriteLine( "Error writing the data." );
            return  -1;
         }

      }
      Console::WriteLine( "The data was written and verified." );
   }
   // Catch the EndOfStreamException and write an error message.
   catch ( EndOfStreamException^ e ) 
   {
      Console::WriteLine( "Error writing the data.\n{0}", e->GetType()->Name );
   }

}

using System;
using System.IO;

class BinaryRW
{
    static void Main()
    {
        int i = 0;

        // Create random data to write to the stream.
        byte[] writeArray = new byte[1000];
        new Random().NextBytes(writeArray);

        BinaryWriter binWriter = new BinaryWriter(new MemoryStream());
        BinaryReader binReader =
            new BinaryReader(binWriter.BaseStream);

        try
        {
            // Write the data to the stream.
            Console.WriteLine("Writing the data.");
            for(i = 0; i < writeArray.Length; i++)
            {
                binWriter.Write(writeArray[i]);
            }

            // Set the stream position to the beginning of the stream.
            binReader.BaseStream.Position = 0;

            // Read and verify the data from the stream.
            for(i = 0; i < writeArray.Length; i++)
            {
                if(binReader.ReadByte() != writeArray[i])
                {
                    Console.WriteLine("Error writing the data.");
                    return;
                }
            }
            Console.WriteLine("The data was written and verified.");
        }

        // Catch the EndOfStreamException and write an error message.
        catch(EndOfStreamException e)
        {
            Console.WriteLine("Error writing the data.\n{0}",
                e.GetType().Name);
        }
    }
}

open System
open System.IO

// Create random data to write to the stream.
let writeArray = Array.zeroCreate<byte> 1000
Random().NextBytes writeArray

let binWriter = new BinaryWriter(new MemoryStream())
let binReader = new BinaryReader(binWriter.BaseStream)

try
    // Write the data to the stream.
    printfn "Writing the data."
    for i = 0 to writeArray.Length - 1 do
        binWriter.Write writeArray[i]

    // Set the stream position to the beginning of the stream.
    binReader.BaseStream.Position <- 0

    let mutable failed = false
    // Read and verify the data from the stream.
    for i = 0 to writeArray.Length - 1 do
        if binReader.ReadByte() <> writeArray[i] then
            printfn "Error writing the data."
            failed <- true
    if not failed then
        printfn "The data was written and verified."

// Catch the EndOfStreamException and write an error message.
with :? EndOfStreamException as e ->
    printfn $"Error writing the data.\n{e.GetType().Name}"

Imports System.IO

Public Class BinaryRW

    Shared Sub Main()
    
        Dim i As Integer = 0

        ' Create random data to write to the stream.
        Dim writeArray(1000) As Byte
        Dim randomGenerator As New Random()
        randomGenerator.NextBytes(writeArray)

        Dim binWriter As New BinaryWriter(New MemoryStream())
        Dim binReader As New BinaryReader(binWriter.BaseStream)

        Try
        
            ' Write the data to the stream.
            Console.WriteLine("Writing the data.")
            For i = 0 To writeArray.Length - 1
                binWriter.Write(writeArray(i))
            Next i

            ' Set the stream position to the beginning of the stream.
            binReader.BaseStream.Position = 0

            ' Read and verify the data from the stream.
            For i = 0 To writeArray.Length - 1
                If binReader.ReadByte() <> writeArray(i) Then
                    Console.WriteLine("Error writing the data.")
                    Return
                End If
            Next i
            Console.WriteLine("The data was written and verified.")

        ' Catch the EndOfStreamException and write an error message.
        Catch ex As EndOfStreamException
            Console.WriteLine("Error writing the data: {0}", _
                ex.GetType().Name)
        End Try
    
    End Sub
End Class

Remarques

BinaryReader ne restaure pas la position du fichier après un échec de lecture.

En raison de conflits de mise en forme des données, l’utilisation de cette méthode avec les encodages suivants n’est pas recommandée :

• UTF-7

• ISO-2022-JP

• ISCII

Pour obtenir la liste des tâches d’E/S courantes, consultez Tâches courantes d’E/S.

Voir aussi

• Fichier et flux de données E/S
• Procédure : lire le texte d’un fichier
• Procédure : écrire du texte dans un fichier