(转)FindFirstChangeNotification,创建一个文件通知对象,该对象用于监视文件系统发生的变化
FindFirstChangeNotification |
| VB声明 | |
| Declare Function FindFirstChangeNotification Lib "kernel32" Alias "FindFirstChangeNotificationA" (ByVal lpPathName As String, ByVal bWatchSubtree As Long, ByVal dwNotifyFilter As Long) As Long | |
| 说明 | |
| 创建一个文件通知对象。该对象用于监视文件系统发生的变化 | |
| 返回值 | |
| Long，如成功，返回一个改变通知对象的句柄；INVALID_HANDLE_VALUE表示失败。会设置GetLastError | |
| 参数表 | |
| 参数 | 类型及说明 |
| lpPathName | String，要监视的目录 |
| bWatchSubtree | Long，如果为TRUE，表示监视lpPathName的所有子目录 |
| dwNotifyFilter | Long，带有前缀FILE_NOTIFY_CHANGE_???前缀的一个或多个常数，它们指定了对象发出信号的条件 |
| 注解 | |
| 用FindCloseChangeNotification函数关闭句柄，不要用CloseHandle函数 |
|
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#include <windows.h>
#include <stdlib.h>
#include <stdio.h>
#include <tchar.h>
void RefreshDirectory(LPTSTR);
void RefreshTree(LPTSTR);
void WatchDirectory(LPTSTR lpDir)
{
DWORD dwWaitStatus;
HANDLE dwChangeHandles[2];
TCHAR lpDrive[4];
TCHAR lpFile[_MAX_FNAME];
TCHAR lpExt[_MAX_EXT];
_tsplitpath(lpDir, lpDrive, NULL, lpFile, lpExt);
lpDrive[2] = (TCHAR)'//';
lpDrive[3] = (TCHAR)'/0';
// Watch the directory for file creation and deletion.
dwChangeHandles[0] = FindFirstChangeNotification(
lpDir, // directory to watch
FALSE, // do not watch subtree
FILE_NOTIFY_CHANGE_FILE_NAME); // watch file name changes
if (dwChangeHandles[0] == INVALID_HANDLE_VALUE)
ExitProcess(GetLastError());
// Watch the subtree for directory creation and deletion.
dwChangeHandles[1] = FindFirstChangeNotification(
lpDrive, // 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 the directory.
// Refresh this directory and restart the notification.
RefreshDirectory(lpDir);
if ( FindNextChangeNotification(
dwChangeHandles[0]) == FALSE )
ExitProcess(GetLastError());
break;
case WAIT_OBJECT_0 + 1:
// A directory was created or deleted in the subtree.
// Refresh the tree and restart the notification.
RefreshTree(lpDrive);
if (FindNextChangeNotification(
dwChangeHandles[1]) == FALSE)
ExitProcess(GetLastError());
break;
default:
ExitProcess(GetLastError());
}
}
}
void RefreshDirectory(LPTSTR lpDir)
{
_tprintf(TEXT("Refresh the directory (%s)./n"), lpDir);
}
void RefreshTree(LPTSTR lpDrive)
{
_tprintf(TEXT("Refresh the directory tree (%s)./n"), lpDrive);
}
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from msdn: 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 file name 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 file name 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()); } }
转自：http://blog.csdn.net/zhaoyawei/article/details/742276