BinaryReader.ReadSingle Méthode
Définition
Important
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Lit une valeur à virgule flottante de 4 octets dans le flux actuel et avance la position actuelle du flux de quatre octets.
public:
virtual float ReadSingle();
public virtual float ReadSingle ();
abstract member ReadSingle : unit -> single
override this.ReadSingle : unit -> single
Public Overridable Function ReadSingle () As Single
Retours
Valeur à virgule flottante de 4 octets lue dans le flux actuel.
Exceptions
La fin du flux est atteinte.
Le flux est fermé.
Une erreur d'E/S s'est produite.
Exemples
L’exemple de code suivant montre comment stocker et récupérer des paramètres d’application dans un fichier.
using System;
using System.IO;
using System.Text;
class ConsoleApplication
{
const string fileName = "AppSettings.dat";
static void Main()
{
WriteDefaultValues();
DisplayValues();
}
public static void WriteDefaultValues()
{
using (var stream = File.Open(fileName, FileMode.Create))
{
using (var writer = new BinaryWriter(stream, Encoding.UTF8, false))
{
writer.Write(1.250F);
writer.Write(@"c:\Temp");
writer.Write(10);
writer.Write(true);
}
}
}
public static void DisplayValues()
{
float aspectRatio;
string tempDirectory;
int autoSaveTime;
bool showStatusBar;
if (File.Exists(fileName))
{
using (var stream = File.Open(fileName, FileMode.Open))
{
using (var reader = new BinaryReader(stream, Encoding.UTF8, false))
{
aspectRatio = reader.ReadSingle();
tempDirectory = reader.ReadString();
autoSaveTime = reader.ReadInt32();
showStatusBar = reader.ReadBoolean();
}
}
Console.WriteLine("Aspect ratio set to: " + aspectRatio);
Console.WriteLine("Temp directory is: " + tempDirectory);
Console.WriteLine("Auto save time set to: " + autoSaveTime);
Console.WriteLine("Show status bar: " + showStatusBar);
}
}
}
open System.IO
open System.Text
let fileName = "AppSettings.dat"
let writeDefaultValues () =
use stream = File.Open(fileName, FileMode.Create)
use writer = new BinaryWriter(stream, Encoding.UTF8, false)
writer.Write 1.250F
writer.Write @"c:\Temp"
writer.Write 10
writer.Write true
let displayValues () =
if File.Exists fileName then
use stream = File.Open(fileName, FileMode.Open)
use reader = new BinaryReader(stream, Encoding.UTF8, false)
let aspectRatio = reader.ReadSingle()
let tempDirectory = reader.ReadString()
let autoSaveTime = reader.ReadInt32()
let showStatusBar = reader.ReadBoolean()
printfn $"Aspect ratio set to: {aspectRatio}"
printfn $"Temp directory is: {tempDirectory}"
printfn $"Auto save time set to: {autoSaveTime}"
printfn $"Show status bar: {showStatusBar}"
writeDefaultValues ()
displayValues ()
Imports System.IO
Module Module1
Const fileName As String = "AppSettings.dat"
Sub Main()
WriteDefaultValues()
DisplayValues()
End Sub
Sub WriteDefaultValues()
Using writer As BinaryWriter = New BinaryWriter(File.Open(fileName, FileMode.Create))
writer.Write(1.25F)
writer.Write("c:\Temp")
writer.Write(10)
writer.Write(True)
End Using
End Sub
Sub DisplayValues()
Dim aspectRatio As Single
Dim tempDirectory As String
Dim autoSaveTime As Integer
Dim showStatusBar As Boolean
If (File.Exists(fileName)) Then
Using reader As BinaryReader = New BinaryReader(File.Open(fileName, FileMode.Open))
aspectRatio = reader.ReadSingle()
tempDirectory = reader.ReadString()
autoSaveTime = reader.ReadInt32()
showStatusBar = reader.ReadBoolean()
End Using
Console.WriteLine("Aspect ratio set to: " & aspectRatio)
Console.WriteLine("Temp directory is: " & tempDirectory)
Console.WriteLine("Auto save time set to: " & autoSaveTime)
Console.WriteLine("Show status bar: " & showStatusBar)
End If
End Sub
End Module
Remarques
BinaryReader ne restaure pas la position du fichier après un échec de lecture.
BinaryReader
lit ce type de données au format little-endian.
Pour obtenir la liste des tâches d’E/S courantes, consultez Tâches courantes d’E/S.