C++ Hook Windows Explorer paste event

Question

I would like to hook Windows Explorer paste event to copy files from a remote connection.

Description: The goal is remote copy/paste files. Like Team Viewer or Remote Desktop. Ctrl+C file on one computer, and Ctrl+V on another...

Answer 1

Well let's break this problem into 3 parts:

1. Detect for clipboard changes:

This is pretty easy, by registering a hook using SetClipboardViewer, Windows will nicely send us an WM_DRAWCLIPBOARD message:

HWND nextClipboardViewer = nullptr;

void HandleClipboardChanges()
{

}

LRESULT CALLBACK WndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
{
    switch (msg)
    {
        case WM_CREATE:
            nextClipboardViewer = SetClipboardViewer(hwnd);
            break;

        case WM_CHANGECBCHAIN:
            if (reinterpret_cast<HWND>(wParam) == nextClipboardViewer)
            {
                nextClipboardViewer = reinterpret_cast<HWND>(lParam);
            }
            else if (nextClipboardViewer != nullptr)
            {
                SendMessage(nextClipboardViewer, msg, wParam, lParam);
            }
            break;

        case WM_DRAWCLIPBOARD:
            HandleClipboardChanges();
            SendMessage(nextClipboardViewer, msg, wParam, lParam);
            break;
    }
}

2. Get the active Windows Explorer directory

In the HandleClipboardChanges function above, we should iterate through all the opened Windows Explorer, check if any of them is focused, and get their current directory, thanks to zett42's answer, we could do this fairly easily:

HWND hWndExplorer = nullptr;
HWND hWndFocused = GetActiveWindow();
std::wstring explorerDir;

for (const auto& info : GetCurrentExplorerFolders())
{
    if (hWndFocused == info.hwnd)
    {
        CComHeapPtr<wchar_t> pPath;
        if (SUCCEEDED(::SHGetNameFromIDList(info.pidl.get(), SIGDN_FILESYSPATH, &pPath)))
        {
            hWndExplorer = info.hwnd;
            explorerDir = pPath;
        }

        break;
    }
}

3. Handle the copy operation and show a progress dialog

For the progress dialog, we will use IProgressDialog, although IOperationsProgressDialog has more features, but it is also more difficult to use, you can consider switching to it.

The hWndParent passed into IProgressDialog::StartProgressDialog could be nullptr, but we will use the explorer's hWnd for consistency.

The below code doesn't check for errors for readability.

// don't forget the include and CoInitialize
#include <atlbase.h>
#include <shlobj_core.h>

CoInitializeEx(nullptr, COINIT_MULTITHREADED);

CComPtr<IProgressDialog> pDialog;

pDialog.CoCreateInstance(CLSID_ProgressDialog);

pDialog->StartProgressDialog(hWndExplorer, nullptr, PROGDLG_AUTOTIME, nullptr);

pDialog->SetTitle(L"Copying from network");
pDialog->SetLine(1, L"Copying 69 files", false, nullptr);

// Do your copy operation here
for (DWORD i = 0; i < 1'000'000; i++)
{
    pDialog->SetProgress(i, 1'000'000);
    pDialog->SetLine(2, L"Copying file_a.txt", false, nullptr);

    // Check if the user had cancelled the operation
    // See also: pDialog->SetCancelMsg()
    // BOOL isUserCancelled = pDialog->HasUserCancelled();
}

pDialog->StopProgressDialog();

Related:

1. Monitoring clipboard
2. How to get the path of an active file explorer window in c++ winapi