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FileSystem.WriteAllText Method (String, String, Boolean)

Writes text to a file.

Namespace:  Microsoft.VisualBasic.FileIO
Assembly:  Microsoft.VisualBasic (in Microsoft.VisualBasic.dll)

public static void WriteAllText(
	string file,
	string text,
	bool append


Type: System.String
File to be written to.
Type: System.String
Text to be written to file.
Type: System.Boolean
True to append to the contents of the file; False to overwrite the contents of the file.


The path is not valid for one of the following reasons: it is a zero-length string; it contains only white space; it contains invalid characters; or it is a device path (starts with \\.\); it ends with a trailing slash.


file is Nothing.


The file does not exist.


The file is in use by another process, or an I/O error occurs.


The path exceeds the system-defined maximum length.


A file or directory name in the path contains a colon (:) or is in an invalid format.


There is not enough memory to write the string to buffer.


The user lacks necessary permissions to view the path.

The UTF-8 encoding is used to write to the file. To specify a different encoding, use a different overload of the WriteAllText method.

If the specified file does not exist, it is created.

If the specified encoding does not match the existing encoding of the file, the specified coding is ignored.


The WriteAllText method opens a file, writes to it, and then closes it. Code that uses the WriteAllText method is simpler than code that uses a StreamWriter object. However, if you are adding strings to a file by using a loop, a StreamWriter object can provide better performance because you only have to open and close the file one time. For more information, see the OpenTextFileWriter method.

The following table lists examples of tasks involving the My.Computer.FileSystem.WriteAllText method.

This example writes the line "This is new text to be added." to the file Test.txt, overwriting any existing text in the file.

"This is new text to be added.", False)

This example writes the names of the files in the Documents and Settings folder to FileList.txt, inserting a carriage return between each for better readability.

For Each foundFile In
        My.Computer.FileSystem.GetFiles("C:\Documents and Settings")
    foundFile = foundFile & vbCrLf
        "C:\Documents and Settings\FileList.txt", foundFile, True)

.NET Framework

Supported in: 4, 3.5, 3.0, 2.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.