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My.Computer.FileSystem.WriteAllBytes Method

Visual Studio 2008

Visual Studio 2005

Writes data to a binary file.

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' Usage
My.Computer.FileSystem.WriteAllBytes(file ,data ,append)
' Declaration
Public Sub WriteAllBytes( _
   ByVal file As String, _
   ByVal data As Byte(), _
   ByVal append As Boolean _
)

Parameters

file: String . Path and name of the file to be written to. Required.
data: Byte . Data to be written to the file. Required.
append: Boolean . Whether to append or overwrite data. Default is False. Required.

Exceptions

The following conditions may create an exception:

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 \\.\) (ArgumentException).
The path is not valid because it is Nothing or ends with a backslash (\) (ArgumentNullException).
The file parameter points to a path that does not exist (FileNotFoundException or DirectoryNotFoundException).
The file is in use by another process or an I/O error occurs (IOException).
The path exceeds the system-defined maximum length (PathTooLongException).
A file or directory name in the path contains a colon (:) or is in an invalid format (NotSupportedException).
The user lacks necessary permissions to view the path (SecurityException).

Remarks

If the append parameter is True, it appends the data to the file; otherwise data in the file is overwritten.

If the specified path, excluding the file name, is not valid, a DirectoryNotFoundException exception will be thrown. If the path is valid but the file does not exist, the file is created.

Note:
The WriteAllBytes method opens a file, writes to it, and then closes it. Code that uses the WriteAllBytes method is simpler than code that uses a BinaryWriter object. However, if you are adding data to a file using a loop, a BinaryWriter object can provide better performance because you only have to open and close the file once.

Tasks

The following table lists an example of a task involving the My.Computer.FileSystem.WriteAllBytes method.

To	See
Write to a binary file	How to: Write to Binary Files in Visual Basic

Example

This example appends the data array CustomerData to the file CollectedData.

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My.Computer.FileSystem.WriteAllBytes _
("C:\MyDocuments\CustomerData", CustomerData, True)

Requirements

Namespace: Microsoft.VisualBasic.MyServices

Class: FileSystemProxy (provides access to FileSystem)

Assembly: Visual Basic Runtime Library (in Microsoft.VisualBasic.dll)

Availability by Project Type

Project type	Available
Windows Application	Yes
Class Library	Yes
Console Application	Yes
Windows Control Library	Yes
Web Control Library	Yes
Windows Service	Yes
Web Site	Yes

Permissions

The following permission may be required.

Permission	Description
FileIOPermission	Controls the ability to access files and folders. Associated enumeration: Unrestricted.

For more information, see Code Access Security and Requesting Permissions.

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My.Computer.FileSystem.WriteAllBytes Method

Availability by Project Type

Tasks

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