My.Computer.FileSystem.ReadAllBytes Method

Article
11/18/2006

Returns the contents of a file as a byte array.

' Usage
Dim value As Byte() = My.Computer.FileSystem.ReadAllBytes(file)
' Declaration
Public Function ReadAllBytes( _
   ByVal file As String _
) As Byte()

Parameters

file
String. File to be read. Required.

Return Value

Byte array containing the contents of the file.

Exceptions

The following conditions may cause an exception to be thrown:

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 file name ends with a trailing slash (ArgumentException).
The path is not valid because it is Nothing (ArgumentNullException).
The file does not exist (FileNotFoundException).
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).
There is not enough memory to write the string to buffer (OutOfMemoryException).
The user lacks necessary permissions to view the path (SecurityException).

Remarks

The ReadAllBytes method of the My.Computer.FileSystem object allows you to read from a binary file. The contents of the file are returned as a byte array.

Do not make decisions about the contents of the file based on the name of the file. For example, the file Form1.vb may not be a Visual Basic source file. Verify all inputs before using the data in your application.

Tasks

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

To	See
Read from a binary file	How to: Read From Binary Files in Visual Basic

Example

This example reads from the file C:/Documents and Settings/selfportrait.jpg.

My.Computer.FileSystem.ReadAllBytes _
("C:/Documents and Settings/selfportrait.jpg")

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 necessary:

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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