Monitoring Changes in a Directory or Directory Tree

The following example monitors the directory tree starting at C:\ for directory name changes. It also monitors the C:\WINDOWS directory for filename changes.

The example uses the FindFirstChangeNotification function to create two notification handles and the WaitForMultipleObjects function to wait on the handles. Whenever a directory is created or deleted in the tree starting at C:\ , the example updates the entire directory tree. Whenever a file is created or deleted in the C:\WINDOWS directory, the example refreshes the WINDOWS directory. The FindNextChangeNotification function restarts the change notification each time the example processes a change.

DWORD dwWaitStatus;

HANDLE dwChangeHandles[2];

// Watch the C:\WINDOWS directory for file creation and

// deletion.

dwChangeHandles[0] = FindFirstChangeNotification(

"C:\\WINDOWS", // directory to watch

FALSE, // do not watch the subtree

FILE_NOTIFY_CHANGE_FILE_NAME); // watch filename changes

if (dwChangeHandles[0] == INVALID_HANDLE_VALUE)

ExitProcess(GetLastError());

// Watch the C:\ subtree for directory creation and

// deletion.

dwChangeHandles[1] = FindFirstChangeNotification(

"C:\\", // directory to watch

TRUE, // watch the subtree

FILE_NOTIFY_CHANGE_DIR_NAME); // watch dir. name changes

if (dwChangeHandles[1] == INVALID_HANDLE_VALUE)

ExitProcess(GetLastError());

// Change notification is set. Now wait on both notification

// handles and refresh accordingly.

while (TRUE)

{

// Wait for notification.

dwWaitStatus = WaitForMultipleObjects(2, dwChangeHandles,

FALSE, INFINITE);

switch (dwWaitStatus) {

case WAIT_OBJECT_0:

// A file was created or deleted in C:\WINDOWS.

// Refresh this directory and restart the

// change notification. RefreshDirectory is an

// application-defined function.

RefreshDirectory("C:\\WINDOWS")

if ( FindNextChangeNotification(

dwChangeHandles[0]) == FALSE )

ExitProcess(GetLastError());

break;

case WAIT_OBJECT_0 + 1:

// A directory was created or deleted in C:\.

// Refresh the directory tree and restart the

// change notification. RefreshTree is an

// application-defined function.

RefreshTree("C:\\");

if (FindNextChangeNotification(

dwChangeHandles[1]) == FALSE)

ExitProcess(GetLastError());

break;

default:

ExitProcess(GetLastError());

}

}

Software for developers

Delphi Components
.Net Components
Software for Android Developers

More information resources

MegaDetailed.Net
Unix Manual Pages
Delphi Examples

Databases for Amazon shops developers

Amazon Categories Database
Browse Nodes Database