Sample Code - WinAPI: File Change Notification Sample Code

[C++] WinAPI: File Change Notification Sample Code
#include <Windows.h>
#include <tchar.h>
#include <shlobj.h>
#include <assert.h>

#define WM_USER_MEDIACHANGED WM_USER+88

typedef struct {
	DWORD dwItem1;    // dwItem1 contains the previous PIDL or name of the folder. 
	DWORD dwItem2;    // dwItem2 contains the new PIDL or name of the folder. 
} SHNOTIFYSTRUCT;


void TRACE(LPCTSTR lpszFormat, ...)
{
	TCHAR lpszBuffer[0x160];
	va_list fmtList;
	va_start(fmtList, lpszFormat);
	_vstprintf_s(lpszBuffer, lpszFormat, fmtList);
	va_end(fmtList);
	::OutputDebugString(lpszBuffer);
}


ULONG g_ulSHChangeNotifyRegister = 0;



LRESULT CALLBACK WndProc(HWND hwnd, UINT iMsg, WPARAM wParam, LPARAM lParam);

int WINAPI _tWinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPTSTR lpszCmdLine, int nCmdShow)
{
	HWND		hwnd;
	MSG			msg;
	WNDCLASS	WndClass;

	WndClass.style = CS_HREDRAW | CS_VREDRAW;
	WndClass.lpfnWndProc = WndProc;
	WndClass.cbClsExtra = 0;
	WndClass.cbWndExtra = 0;
	WndClass.hInstance = hInstance;
	WndClass.hIcon = LoadIcon(NULL, IDI_APPLICATION);
	WndClass.hCursor = LoadCursor(NULL, IDC_ARROW);
	WndClass.hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH);
	WndClass.lpszMenuName = NULL;
	WndClass.lpszClassName = _T("Window Class Name");

	RegisterClass(&WndClass);

	hwnd = CreateWindow(_T("Window Class Name"),
		_T("Window Title Name"),
		WS_OVERLAPPEDWINDOW,
		CW_USEDEFAULT,
		CW_USEDEFAULT,
		CW_USEDEFAULT,
		CW_USEDEFAULT,
		NULL,
		NULL,
		hInstance,
		NULL
		);

	ShowWindow(hwnd, nCmdShow);
	UpdateWindow(hwnd);

	LPITEMIDLIST ppidl;
	if (SHGetSpecialFolderLocation(hwnd, CSIDL_DESKTOP, &ppidl) == NOERROR)
	{
		SHChangeNotifyEntry shCNE;
		shCNE.pidl = ppidl;
		shCNE.fRecursive = TRUE;

		// Returns a positive integer registration identifier (ID).
		// Returns zero if out of memory or in response to invalid parameters.
		g_ulSHChangeNotifyRegister = SHChangeNotifyRegister(hwnd,					// Hwnd to receive notification
			SHCNE_DISKEVENTS,														// Event types of interest (sources)
			SHCNE_UPDATEITEM,														// Events of interest - use SHCNE_ALLEVENTS for all events
			WM_USER_MEDIACHANGED,													// Notification message to be sent upon the event
			1,																		// Number of entries in the pfsne array
			&shCNE);																// Array of SHChangeNotifyEntry structures that 
		// contain the notifications. This array should 
		// always be set to one when calling SHChnageNotifyRegister
		// or SHChangeNotifyDeregister will not work properly.

		assert(g_ulSHChangeNotifyRegister != 0);    // Shell notification failed
	}
	else
		assert(FALSE);    // Failed to get desktop location



	while (GetMessage(&msg, NULL, 0, 0))
	{
		TranslateMessage(&msg);
		DispatchMessage(&msg);
	}
	return (int)msg.wParam;
}


LRESULT CALLBACK WndProc(HWND hwnd, UINT iMsg, WPARAM wParam, LPARAM lParam)
{
	switch (iMsg)
	{
	case WM_CREATE:
		break;
	case WM_DESTROY:
		PostQuitMessage(0);
		break;
	case WM_USER_MEDIACHANGED:
	{
		TCHAR szPath[MAX_PATH];
		SHNOTIFYSTRUCT *shns = (SHNOTIFYSTRUCT *)wParam;

		switch (lParam)
		{
		case SHCNE_UPDATEITEM:        // 
		{
			SHGetPathFromIDList((struct _ITEMIDLIST *)shns->dwItem1, szPath);
			if (_tcslen(szPath) != 0)
			{
				// Process strPath as required, for now a simple message box
				MessageBox(hwnd, szPath, _T("Notify"), MB_OK);
				
				TRACE(_T("%s\n"), szPath);
				
			}
		}
		//case SHCNE_xxxx:  Add other events processing here
		}
	}
		break;
	}

	return DefWindowProc(hwnd, iMsg, wParam, lParam);
}