File Notification Sample
This sample uses the FileSystemWatcher class to respond when files are created, deleted, modified or renamed.
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.gif "Security note") Security Note: |
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This sample code is intended to illustrate a concept, and it shows only the code that is relevant to that concept. It may not meet the security requirements for a specific environment, and it should not be used exactly as shown. We recommend that you add security and error-handling code to make your projects more secure and robust. Microsoft provides this sample code "AS IS" with no warranties. |
To run this sample
Press F5.
Use the controls on the right to change files that are being watched.
Use Windows Explorer to change files that are being watched. It makes no difference how the file changes are accomplished.
Demonstrates
The sample form enables you to set properties of the FileSystemWatcher class. This includes the following:
Path The file system path to be "watched" by the object.
Filter The types of files to be watched. The default is *.*.
NotifyFilter The types of changes to watch for. This property can be zero or more values from the System.IO.NotifyFilters enumeration, combined together. By default, the FileSystemWatcher detects FileName, DirectoryName, and LastWrite changes.
IncludeSubdirectories Indicates whether the monitoring should include directories underneath the selected path.
EnableRaisingEvents If true, the object monitors for file-system changes and raises events as they occur. Basically, this is the "on/off switch". In this demonstration, this property is controlled by using a CheckBox control displayed as a toggle button.
The controls on the form let you generate events by creating, deleting, renaming, and modifying files. This component tray of the form includes a FileSystemWatcher component, found in the Components tab on the Toolbox. Using the component makes it simple to set properties at design time by using the Properties window.
The Create, Rename, Modify, and Delete Sample File buttons on the form are used to generate the FileSystemWatcher events. These buttons create temporary files in the selected folder. Use the Delete All Sample Files button to clean up all remaining sample files when you have finished. Five of the FileSystemWatcher events are handled in this sample:
Created, Changed, and Deleted These three events are all handled by the same event handler, HandleChangedCreatedDeleted. The details of the event are displayed on the form.
Renamed The old and new names are displayed.
Error The exception message is displayed.