Programmatically delete item from Windows Recycle Bin without UI dialog - c++

Question

I'm using IContextMenu with "delete" verb to erase items from recycle bin, but it brings up the UI dialog even if I useCMIC_MASK_FLAG_NO_UI flag. Is there another way to delete files from recycle bin without showing the dialog?
IContextMenu* contextMenu;
recycleBin->GetUIObjectOf(0, 1, (LPCITEMIDLIST*)(&pidl), IID_IContextMenu, 0, (LPVOID *)&contextMenu);
CMINVOKECOMMANDINFO ci;
memset(&ci, 0, sizeof(ci));
ci.fMask = CMIC_MASK_FLAG_NO_UI;
ci.cbSize = sizeof(CMINVOKECOMMANDINFO);
ci.lpVerb = "delete";
contextMenu->InvokeCommand(&ci);
contextMenu->Release();
The full code including recycle bin object initialization and items enumeration is on gist

Answer 1

You can install a WH_CBT hook, and in its callback watch for an nCode of HCBT_CREATEWND. If you get a matching class name ('#32770 (Dialog)' ?) and a matching title either return a nonzero value from the callback, you can send BM_CLICK to click Yes button and the dialog will be closed automatically.
Code Sample:
main.cpp
#include <iostream>
#include <windows.h>
#include <Ole2.h>
#include <shlobj.h>
#include <shlwapi.h>
#include <string>
#pragma comment(lib,"Shlwapi.lib")
HHOOK g_hhook;
int main()
{
OleInitialize(0);
HINSTANCE hinstDLL = LoadLibrary(TEXT("D:\\xxx\\Dll_WH_CBT\\Debug\\Dll_WH_CBT.dll"));
HHOOK(*AttachHookProc)(DWORD);
AttachHookProc = (HHOOK(*)(DWORD)) GetProcAddress(hinstDLL, "AttachHook");
void(*RemoveHooks)(DWORD);
RemoveHooks = (void(*)(DWORD))GetProcAddress(hinstDLL, "RemoveHooks");
IShellFolder* desktop;
if (FAILED(SHGetDesktopFolder(&desktop))) {
std::cerr << "Failed to get desktop fodler" << std::endl;
return -1;
}
...
IEnumIDList* enumFiles;
if (FAILED(recycleBin->EnumObjects(0, SHCONTF_FOLDERS | SHCONTF_NONFOLDERS |
SHCONTF_INCLUDEHIDDEN, &enumFiles)))
{
std::cerr << "Could not enumerate recycle bin objects" << std::endl;
recycleBin->Release();
return -1;
}
AttachHookProc(0);
...
RemoveHooks(0);
enumFiles->Release();
recycleBin->Release();
OleUninitialize();
return 0;
}
Dll:
// dllmain.cpp : Defines the entry point for the DLL application.
#include "pch.h"
#include <Windows.h>
HMODULE thisModule;
HHOOK g_hhook;
LRESULT CALLBACK CBTProc(int nCode, WPARAM wParam, LPARAM lParam)
{
switch (nCode)
{
case HCBT_CREATEWND:
{
HWND File_Window = FindWindow(L"#32770", L"Delete File");
HWND Folder_Window = FindWindow(L"#32770", L"Delete Folder");
if (File_Window)
{
HWND yes = FindWindowEx(File_Window, NULL, L"Button", L"&Yes");
SendMessage(yes, BM_CLICK, 0, 0);
SendMessage(yes, BM_CLICK, 0, 0);
}
if (Folder_Window)
{
HWND yes = FindWindowEx(Folder_Window, NULL, L"Button", L"&Yes");
SendMessage(yes, BM_CLICK, 0, 0);
SendMessage(yes, BM_CLICK, 0, 0);
}
break;
}
default:
break;
}
return CallNextHookEx(g_hhook, nCode, wParam, lParam);
}
#ifdef __cplusplus //If used by C++ code.
extern "C" { //we need to export the C interface
#endif
_declspec(dllexport) HHOOK AttachHook(DWORD threadID) {
g_hhook = SetWindowsHookEx(WH_CBT, CBTProc, thisModule, threadID);
return g_hhook;
}
#ifdef __cplusplus
}
#endif
extern "C" { //we need to export the C interface
__declspec(dllexport) void RemoveHooks(DWORD)
{
UnhookWindowsHookEx(g_hhook);
}
}
BOOL APIENTRY DllMain( HMODULE hModule,
DWORD ul_reason_for_call,
LPVOID lpReserved
)
{
thisModule = hModule;
switch (ul_reason_for_call)
{
case DLL_PROCESS_ATTACH:
case DLL_THREAD_ATTACH:
case DLL_THREAD_DETACH:
case DLL_PROCESS_DETACH:
break;
}
return TRUE;
}