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FileSystemWatcher.FileSystemWatcher(String, String) Constructor

Initializes a new instance of the FileSystemWatcher class, given the specified directory and type of files to monitor.

Namespace: System.IO
Assembly: System (in system.dll)

public FileSystemWatcher (
	string path,
	string filter
public FileSystemWatcher (
	String path, 
	String filter
public function FileSystemWatcher (
	path : String, 
	filter : String
Not applicable.



The directory to monitor, in standard or Universal Naming Convention (UNC) notation.


The type of files to watch. For example, "*.txt" watches for changes to all text files.

Exception typeCondition


The path parameter is a null reference (Nothing in Visual Basic).


The filter parameter is a null reference (Nothing in Visual Basic).


The path parameter is an empty string ("").


The path specified through the path parameter does not exist.


The component will not watch the specified directory until the Path is set, and EnableRaisingEvents is true.

The component can watch files on your personal computer, a network drive, or a remote computer.

You cannot watch a remote computer that does not have Windows NT or Windows 2000. You cannot watch a remote Windows NT 4.0 computer from a Windows NT 4.0 computer.

  • SecurityAction.LinkDemand  for full trust for the immediate caller. This member cannot be used by partially trusted code.

Windows 98, Windows Server 2000 SP4, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.

.NET Framework

Supported in: 3.0, 2.0, 1.1, 1.0