Procédure : Écrire du texte dans un fichierHow to: Write text to a file

Cette rubrique présente différentes façons d’écrire du texte dans un fichier pour une application .NET.This topic shows different ways to write text to a file for a .NET app.

Les classes et méthodes suivantes sont généralement utilisées pour écrire du texte dans un fichier :The following classes and methods are typically used to write text to a file:

Notes

Les exemples suivants ne montrent que la quantité minimale de code nécessaire.The following examples show only the minimum amount of code needed. Une application réelle fournit généralement une vérification des erreurs et une gestion des exceptions plus robuste.A real-world app usually provides more robust error checking and exception handling.

Exemple : écrire du texte avec StreamWriter de façon synchroneExample: Synchronously write text with StreamWriter

L’exemple suivant montre comment utiliser la classe StreamWriter pour écrire, ligne par ligne, du texte de façon synchrone dans un nouveau fichier.The following example shows how to use the StreamWriter class to synchronously write text to a new file one line at a time. Étant donné que l’objet StreamWriter est déclaré et instancié dans une instruction using, la méthode Dispose est appelée, ce qui vide et ferme automatiquement le flux.Because the StreamWriter object is declared and instantiated in a using statement, the Dispose method is invoked, which automatically flushes and closes the stream.

using System;
using System.IO;

class Program
{
    static void Main(string[] args)
    {
    
        // Create a string array with the lines of text
        string[] lines = { "First line", "Second line", "Third line" };

        // Set a variable to the Documents path.
        string docPath =
          Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments);

        // Write the string array to a new file named "WriteLines.txt".
        using (StreamWriter outputFile = new StreamWriter(Path.Combine(docPath, "WriteLines.txt")))
        {
            foreach (string line in lines)
                outputFile.WriteLine(line);
        }
    }
}
// The example creates a file named "WriteLines.txt" with the following contents:
// First line
// Second line
// Third line
Imports System.IO

Class WriteText

    Public Shared Sub Main()

        ' Create a string array with the lines of text
        Dim lines() As String = {"First line", "Second line", "Third line"}

        ' Set a variable to the Documents path.
        Dim docPath As String = Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments)

        ' Write the string array to a new file named "WriteLines.txt".
        Using outputFile As New StreamWriter(Path.Combine(docPath, Convert.ToString("WriteLines.txt")))
            For Each line As String In lines
                outputFile.WriteLine(line)
            Next
        End Using

    End Sub

End Class

' The example creates a file named "WriteLines.txt" with the following contents:
' First line
' Second line
' Third line

Exemple : ajouter du texte avec StreamWriter de façon synchroneExample: Synchronously append text with StreamWriter

L’exemple suivant montre comment utiliser la classe StreamWriter pour ajouter du texte de façon synchrone au fichier texte créé dans le premier exemple.The following example shows how to use the StreamWriter class to synchronously append text to the text file created in the first example.

using System;
using System.IO;

class Program
{
    static void Main(string[] args)
    {

        // Set a variable to the Documents path.
        string docPath = Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments);

        // Append text to an existing file named "WriteLines.txt".
        using (StreamWriter outputFile = new StreamWriter(Path.Combine(docPath, "WriteLines.txt"), true))
        {
            outputFile.WriteLine("Fourth Line");
        }
    }
}
// The example adds the following line to the contents of "WriteLines.txt":
// Fourth Line
Imports System.IO

Class AppendText

    Public Shared Sub Main()

        ' Set a variable to the Documents path.
        Dim docPath As String =
            Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments)

        ' Append text to an existing file named "WriteLines.txt".
        Using outputFile As New StreamWriter(Path.Combine(docPath, Convert.ToString("WriteLines.txt")), True)
            outputFile.WriteLine("Fourth Line")
        End Using

    End Sub

End Class

' The example adds the following line to the contents of "WriteLines.txt":
' Fourth Line

Exemple : écrire du texte avec StreamWriter de façon asynchroneExample: Asynchronously write text with StreamWriter

L’exemple suivant montre comment écrire du texte de façon asynchrone dans un nouveau fichier à l’aide de la classe StreamWriter .The following example shows how to asynchronously write text to a new file using the StreamWriter class. Pour appeler la méthode WriteAsync, l’appel de méthode doit se trouver dans une méthode async.To invoke the WriteAsync method, the method call must be within an async method. L’exemple C# nécessite C# 7.1 ou version ultérieure, qui ajoute la prise en charge du modificateur async sur le point d’entrée du programme.The C# example requires C# 7.1 or later, which adds support for the async modifier on the program entry point.

using System;
using System.IO;
using System.Threading.Tasks;

class Program
{
    static async Task Main()
    {
        // Set a variable to the Documents path.
        string docPath = Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments);

        // Write the specified text asynchronously to a new file named "WriteTextAsync.txt".
        using (StreamWriter outputFile = new StreamWriter(Path.Combine(docPath, "WriteTextAsync.txt")))
        {
            await outputFile.WriteAsync("This is a sentence.");
        }
    }
}
// The example creates a file named "WriteTextAsync.txt" with the following contents:
// This is a sentence.
Imports System.IO

Public Module Example
    Public Sub Main()
        WriteTextAsync()
    End Sub

    Async Sub WriteTextAsync()
        ' Set a variable to the Documents path.
        Dim docPath As String = Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments)

        ' Write the text asynchronously to a new file named "WriteTextAsync.txt".
        Using outputFile As New StreamWriter(Path.Combine(docPath, Convert.ToString("WriteTextAsync.txt")))
            Await outputFile.WriteAsync("This is a sentence.")
        End Using
    End Sub
End Module

' The example creates a file named "WriteTextAsync.txt" with the following contents:
' This is a sentence.

Exemple : écrire et ajouter du texte avec la classe FileExample: Write and append text with the File class

L’exemple suivant montre comment écrire du texte dans un nouveau fichier et ajouter de nouvelles lignes de texte à ce même fichier à l’aide de la classe File .The following example shows how to write text to a new file and append new lines of text to the same file using the File class. Les méthodes WriteAllText et AppendAllLines ouvrent et ferment automatiquement le fichier.The WriteAllText and AppendAllLines methods open and close the file automatically. Si le chemin que vous fournissez à la méthode WriteAllText existe déjà, le fichier est remplacé.If the path you provide to the WriteAllText method already exists, the file is overwritten.

using System;
using System.IO;

class Program
{
    static void Main(string[] args)
    {
        // Create a string with a line of text.
        string text = "First line" + Environment.NewLine;

        // Set a variable to the Documents path.
        string docPath = Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments);

        // Write the text to a new file named "WriteFile.txt".
        File.WriteAllText(Path.Combine(docPath, "WriteFile.txt"), text);

        // Create a string array with the additional lines of text
        string[] lines = { "New line 1", "New line 2" };

        // Append new lines of text to the file
        File.AppendAllLines(Path.Combine(docPath, "WriteFile.txt"), lines);
    }
}
// The example creates a file named "WriteFile.txt" with the contents:
// First line
// And then appends the following contents:
// New line 1
// New line 2
Imports System.IO

Class WriteFile

    Public Shared Sub Main()

        ' Create a string array with the lines of text
        Dim text As String = "First line" & Environment.NewLine

        ' Set a variable to the Documents path.
        Dim docPath As String = Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments)

        ' Write the text to a new file named "WriteFile.txt".
        File.WriteAllText(Path.Combine(docPath, Convert.ToString("WriteFile.txt")), text)

        ' Create a string array with the additional lines of text
        Dim lines() As String = {"New line 1", "New line 2"}

        ' Append new lines of text to the file
        File.AppendAllLines(Path.Combine(docPath, Convert.ToString("WriteFile.txt")), lines)

    End Sub

End Class

' The example creates a file named "WriteFile.txt" with the following contents:
' First line
' And then appends the following contents:
' New line 1
' New line 2

Voir aussiSee also