How to find the names of all files from the clipboard - c++

Question

I just created an MFC application to find the file names from the clip board
AddClipboardFormatListener(AfxGetApp()->m_pMainWnd->m_hWnd);
LRESULT Cfile_trackerDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
{
switch(message)
{
case WM_CLIPBOARDUPDATE:
{
AfxBeginThread(FileArrival, NULL);
break;
}
case WM_CHANGECBCHAIN:
{
AfxBeginThread(FileArrival, NULL);
break;
}
}
return CDialog::WindowProc(message, wParam, lParam);
}
UINT FileArrival(LPVOID param)
{
TCHAR lpszFileName[MAX_PATH];
char *szTime;
time_t thistime;
OpenClipboard(0);
HGLOBAL hGlobal = (HGLOBAL)GetClipboardData(CF_HDROP);
if (hGlobal)
{
HDROP hDrop = (HDROP)GlobalLock(hGlobal);
if (hDrop)
{
time(&thistime);
szTime = ctime(&thistime);
DragQueryFile(hDrop, 0, lpszFileName, MAX_PATH);
WriteLog((char*)lpszFileName,1);
GlobalUnlock(hGlobal);
}
CloseClipboard();
}
return 0;
}
This code is working fine when we copy 1 file , but when we copy multiple files it only shows the first file. Is there is any method to find out all the file names that copied to the clipboard.

Answer 1

You use this to find the number of files that were dropped:
UINT fileCount = DragQueryFile(hDrop, 0xFFFFFFFF, nullptr, 0);
With this information, you can allocate an array of strings and store each filename into a string in the array:
TCHAR** filenames;
// other code . . .
filenames = malloc(fileCount * sizeof(TCHAR*));
// other code . . .
for (UINT i = 0; i < fileCount; ++i) {
UINT filenameLength = DragQueryFile(hDrop, i, nullptr, 0);
filenames[i] = malloc(filenameLength);
DragQueryFile(hDrop, i, filenames[i], filenameLength);
}
I figured this all out from reading the documentation.
EDIT: To use the C++ standard library here (prevents having to manually free allocated memory), you can use the following code:
std::vector<std::basic_string<TCHAR> > filenames(fileCount);
// other code . . .
for (UINT i = 0; i < fileCount; ++i) {
UINT filenameLength = DragQueryFile(hDrop, i, nullptr, 0);
filenames[i].reserve(filenameLength);
DragQueryFile(hDrop, i, &(filenames[i][0]), filenameLength);
// Uncomment the below line and comment the above line if you can use C++17 features
// DragQueryFile(hDrop, i, filenames[i].data(), filenameLength);
}