File.WriteAllText File.WriteAllText File.WriteAllText File.WriteAllText Method

Definition

Creates a new file, write the contents to the file, and then closes the file. If the target file already exists, it is overwritten.

Overloads

WriteAllText(String, String) WriteAllText(String, String) WriteAllText(String, String) WriteAllText(String, String)

Creates a new file, writes the specified string to the file, and then closes the file. If the target file already exists, it is overwritten.

WriteAllText(String, String, Encoding) WriteAllText(String, String, Encoding) WriteAllText(String, String, Encoding)

Creates a new file, writes the specified string to the file using the specified encoding, and then closes the file. If the target file already exists, it is overwritten.

WriteAllText(String, String) WriteAllText(String, String) WriteAllText(String, String) WriteAllText(String, String)

Creates a new file, writes the specified string to the file, and then closes the file. If the target file already exists, it is overwritten.

public:
 static void WriteAllText(System::String ^ path, System::String ^ contents);
public static void WriteAllText (string path, string contents);
static member WriteAllText : string * string -> unit
Public Shared Sub WriteAllText (path As String, contents As String)
Parameters
path
String String String String

The file to write to.

contents
String String String String

The string to write to the file.

Exceptions

path is a zero-length string, contains only white space, or contains one or more invalid characters as defined by InvalidPathChars.

The specified path, file name, or both exceed the system-defined maximum length.

The specified path is invalid (for example, it is on an unmapped drive).

An I/O error occurred while opening the file.

path specified a file that is read-only.

-or-

This operation is not supported on the current platform.

-or-

path specified a directory.

-or-

The caller does not have the required permission.

The caller does not have the required permission.

Examples

The following code example demonstrates the use of the WriteAllText method to write text to a file. In this example a file is created, if it doesn't already exist, and text is added to it.

using System;
using System.IO;
using System.Text;

class Test
{
    public static void Main()
    {
        string path = @"c:\temp\MyTest.txt";

        // This text is added only once to the file.
        if (!File.Exists(path))
        {
            // Create a file to write to.
            string createText = "Hello and Welcome" + Environment.NewLine;
            File.WriteAllText(path, createText);
        }

        // This text is always added, making the file longer over time
        // if it is not deleted.
        string appendText = "This is extra text" + Environment.NewLine;
        File.AppendAllText(path, appendText);

        // Open the file to read from.
        string readText = File.ReadAllText(path);
        Console.WriteLine(readText);
    }
}
Imports System
Imports System.IO
Imports System.Text

Public Class Test
    Public Shared Sub Main()
        Dim path As String = "c:\temp\MyTest.txt"

        ' This text is added only once to the file.
        If File.Exists(path) = False Then

            ' Create a file to write to.
            Dim createText As String = "Hello and Welcome" + Environment.NewLine
            File.WriteAllText(path, createText)
        End If

        ' This text is always added, making the file longer over time
        ' if it is not deleted.
        Dim appendText As String = "This is extra text" + Environment.NewLine
        File.AppendAllText(path, appendText)

        ' Open the file to read from.
        Dim readText As String = File.ReadAllText(path)
        Console.WriteLine(readText)
    End Sub
End Class

Remarks

This method uses UTF-8 encoding without a Byte-Order Mark (BOM), so using the GetPreamble method will return an empty byte array. If it is necessary to include a UTF-8 identifier, such as a byte order mark, at the beginning of a file, use the WriteAllText(String, String, Encoding) method overload with UTF8 encoding.

Given a string and a file path, this method opens the specified file, writes the string to the file, and then closes the file.

Security

FileIOPermission
for access to write to a file or directory. Associated enumeration: Write

WriteAllText(String, String, Encoding) WriteAllText(String, String, Encoding) WriteAllText(String, String, Encoding)

Creates a new file, writes the specified string to the file using the specified encoding, and then closes the file. If the target file already exists, it is overwritten.

public:
 static void WriteAllText(System::String ^ path, System::String ^ contents, System::Text::Encoding ^ encoding);
public static void WriteAllText (string path, string contents, System.Text.Encoding encoding);
static member WriteAllText : string * string * System.Text.Encoding -> unit
Parameters
path
String String String String

The file to write to.

contents
String String String String

The string to write to the file.

encoding
Encoding Encoding Encoding Encoding

The encoding to apply to the string.

Exceptions

path is a zero-length string, contains only white space, or contains one or more invalid characters as defined by InvalidPathChars.

The specified path, file name, or both exceed the system-defined maximum length.

The specified path is invalid (for example, it is on an unmapped drive).

An I/O error occurred while opening the file.

path specified a file that is read-only.

-or-

This operation is not supported on the current platform.

-or-

path specified a directory.

-or-

The caller does not have the required permission.

The caller does not have the required permission.

Examples

The following code example demonstrates the use of the WriteAllText method to write text to a file. In this example a file is created, if it doesn't already exist, and text is added to it.

using System;
using System.IO;
using System.Text;

class Test
{
    public static void Main()
    {
        string path = @"c:\temp\MyTest.txt";

        // This text is added only once to the file.
        if (!File.Exists(path))
        {
            // Create a file to write to.
            string createText = "Hello and Welcome" + Environment.NewLine;
            File.WriteAllText(path, createText, Encoding.UTF8);
        }

        // This text is always added, making the file longer over time
        // if it is not deleted.
        string appendText = "This is extra text" + Environment.NewLine;
        File.AppendAllText(path, appendText, Encoding.UTF8);

        // Open the file to read from.
        string readText = File.ReadAllText(path);
        Console.WriteLine(readText);
    }
}
Imports System
Imports System.IO
Imports System.Text

Public Class Test
    Public Shared Sub Main()
        Dim path As String = "c:\temp\MyTest.txt"
        Dim sw As StreamWriter

        ' This text is added only once to the file.
        If File.Exists(path) = False Then

            ' Create a file to write to.
            Dim createText As String = "Hello and Welcome" + Environment.NewLine
            File.WriteAllText(path, createText, Encoding.UTF8)
        End If

        ' This text is always added, making the file longer over time
        ' if it is not deleted.
        Dim appendText As String = "This is extra text" + Environment.NewLine
        File.AppendAllText(path, appendText, Encoding.UTF8)

        ' Open the file to read from.
        Dim readText As String = File.ReadAllText(path)
        Console.WriteLine(readText)
    End Sub
End Class

Remarks

Given a string and a file path, this method opens the specified file, writes the string to the file using the specified encoding, and then closes the file. The file handle is guaranteed to be closed by this method, even if exceptions are raised.

Security

FileIOPermission
for access to write to a file or directory. Associated enumeration: Write

Applies to