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.NET Development
.NET Framework 3.5
System.IO Namespace
File Class
File Methods
 ReadAllBytes Method
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This page is specific to
Microsoft Visual Studio 2008/.NET Framework 3.5

Other versions are also available for the following:
.NET Framework Class Library
File..::.ReadAllBytes Method

Opens a binary file, reads the contents of the file into a byte array, and then closes the file.

Namespace:  System.IO
Assembly:  mscorlib (in mscorlib.dll)
Visual Basic (Declaration)
Public Shared Function ReadAllBytes ( _
    path As String _
) As Byte()
Visual Basic (Usage)
Dim path As String
Dim returnValue As Byte()

returnValue = File.ReadAllBytes(path)
C#
public static byte[] ReadAllBytes(
    string path
)
Visual C++
public:
static array<unsigned char>^ ReadAllBytes(
    String^ path
)
JScript
public static function ReadAllBytes(
    path : String
) : byte[]

Parameters

path
Type: System..::.String
The file to open for reading.

Return Value

Type: array<System..::.Byte>[]()[]
A byte array containing the contents of the file.
ExceptionCondition
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 nullNothingnullptra null reference (Nothing in Visual Basic).

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

This operation is not supported on the current platform.

-or-

path specified a directory.

-or-

The caller does not have the required permission.

FileNotFoundException

The file specified in path was not found.

NotSupportedException

path is in an invalid format.

SecurityException

The caller does not have the required permission.

Given a file path, this method opens the file, reads the contents of the file into a byte array, and then closes the file.

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98

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

.NET Framework

Supported in: 3.5, 3.0, 2.0
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Also throws IOException when the file is too large      David M. Kean - MSFT   |   Edit   |   Show History
This method also throws IOException when the file is greater than 2 GB (2,147,483,648 bytes).
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