Instrukcje: Zapisywanie tekstu do plikuHow to: Write text to a file

W tym temacie przedstawiono różne sposoby zapisywanie tekstu do pliku dla aplikacji platformy .NET.This topic shows different ways to write text to a file for a .NET app.

Następujące klasy i metody są zwykle używane do zapisywanie tekstu do pliku:The following classes and methods are typically used to write text to a file:

Uwaga

W poniższych przykładach pokazano minimalnej ilości kodu.The following examples show only the minimum amount of code needed. Aplikacja rzeczywistych zwykle zapewnia bardziej niezawodne sprawdzanie błędów i wyjątków.A real-world app usually provides more robust error checking and exception handling.

Przykład: Synchronicznie wpisać tekst za pomocą StreamWriterExample: Synchronously write text with StreamWriter

Poniższy przykład pokazuje, jak używać StreamWriter klasy synchronicznie zapisywanie tekstu do nowego jeden wiersz pliku naraz.The following example shows how to use the StreamWriter class to synchronously write text to a new file one line at a time. Ponieważ StreamWriter obiektu jest zadeklarowana i tworzone w using instrukcji Dispose wywoływana jest metoda, która automatycznie opróżnia i zamyka strumienia.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

Przykład: Synchronicznie dołączyć tekst za pomocą StreamWriterExample: Synchronously append text with StreamWriter

Poniższy przykład pokazuje, jak używać StreamWriter klasy synchronicznie dołączyć tekst do pliku tekstowego, utworzony w pierwszym przykładzie.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

Przykład: Asynchronicznie zapis tekstu za pomocą StreamWriterExample: Asynchronously write text with StreamWriter

Poniższy przykład pokazuje, jak asynchronicznie zapisywanie tekstu do nowego pliku przy użyciu StreamWriter klasy.The following example shows how to asynchronously write text to a new file using the StreamWriter class. Aby wywołać WriteAsync metody wywołania metody które muszą znajdować się w async metody.To invoke the WriteAsync method, the method call must be within an async method. C# Przykład wymaga C# 7.1 lub nowszej, który dodaje obsługę async modyfikator dla punktu wejścia programu.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.

Przykład: Pisanie i dołączyć tekst z klasą plikówExample: Write and append text with the File class

Poniższy przykład pokazuje, jak zapisywanie tekstu do nowego pliku i dołączyć nowe wiersze tekstu do tego samego pliku przy użyciu File klasy.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. WriteAllText i AppendAllLines metod Otwórz i zamknij plik automatycznie.The WriteAllText and AppendAllLines methods open and close the file automatically. Jeśli ścieżka uzyskiwanie WriteAllText metody już istnieje, zostanie on zastąpiony.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

Zobacz takżeSee also