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FileStream.Lock Method

Prevents other processes from changing the FileStream.

Namespace:  System.IO
Assembly:  mscorlib (in mscorlib.dll)
public function Lock(
	position : long, 
	length : long


Type: System.Int64

The beginning of the range to lock. The value of this parameter must be equal to or greater than zero (0).

Type: System.Int64

The range to be locked.


position or length is negative.


The file is closed.


The process cannot access the file because another process has locked a portion of the file.

Locking a range of a file stream gives the threads of the locking process exclusive access to that range of the file stream.

For a list of common I/O tasks, see Common I/O Tasks.

The following code example demonstrates how to lock part of a file so another process cannot access that part of the file even though it has read/write access to the file. Run the program simultaneously in different command windows and investigate using the different console input options.

No code example is currently available or this language may not be supported.

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, 1.1, 1.0
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