File.WriteAllText Method (String, String)

 
System_CAPS_noteNote

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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.

Namespace:   System.IO
Assembly:  mscorlib (in mscorlib.dll)

Public Shared Sub WriteAllText (
	path As String,
	contents As String
)

Parameters

path
Type: System.String

The file to write to.

contents
Type: System.String

The string to write to the file.

Exception Condition
ArgumentException

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

ArgumentNullException

path is null or contents is empty.

PathTooLongException

The specified path, file name, or both exceed the system-defined maximum length. For example, on Windows-based platforms, paths must be less than 248 characters, and file names must be less than 260 characters.

DirectoryNotFoundException

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

IOException

An I/O error occurred while opening the file.

UnauthorizedAccessException

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.

NotSupportedException

path is in an invalid format.

SecurityException

The caller does not have the required permission.

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.

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.

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

FileIOPermission

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

Universal Windows Platform
Available since 10
.NET Framework
Available since 2.0
Silverlight
Available since 4.0
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