Using a CBT Hook to modify a Windows dialog box.

MessageBoxHook.cpp

#pragma comment(linker, "\"/manifestdependency:type='win32' name='Microsoft.Windows.Common-Controls' version='6.0.0.0' processorArchitecture='*' publicKeyToken='6595b64144ccf1df' language='*'\"")

#define WIN32_LEAN_AND_MEAN             // Exclude rarely-used stuff from Windows headers
#include <SDKDDKVer.h>
#include <windows.h>
#include "resource.h"

INT_PTR CALLBACK AboutProc(
	HWND hDlg,
	UINT message,
	WPARAM wParam,
	LPARAM /*lParam*/)
{
	switch (message)
	{
	case WM_INITDIALOG:
		return (INT_PTR)TRUE;

	case WM_COMMAND:
		if (LOWORD(wParam) == IDOK || LOWORD(wParam) == IDCANCEL)
		{
			EndDialog(hDlg, LOWORD(wParam));
			return (INT_PTR)TRUE;
		}
		break;
	}
	return (INT_PTR)FALSE;
}

HHOOK g_hHook = NULL;

LRESULT CALLBACK HookProc(
	int nCode, 
	WPARAM wParam, 
	LPARAM lParam)
{
	if (nCode < 0)
	{
		return CallNextHookEx(g_hHook, nCode, wParam, lParam);
	}

	switch (nCode)
	{
	case HCBT_ACTIVATE:
		HWND hwnd = (HWND)wParam;

		SetWindowText(hwnd, L"Hook Caption");

		HWND hwndButton; 
		int x = 145;
		const unsigned int cx = 40;
		const unsigned int spacing = 2;

		hwndButton = GetDlgItem(hwnd, IDYES);
		SetWindowText(hwndButton, L"👍");
		MoveWindow(hwndButton, x, 83, cx, 32, TRUE);
		x += cx + spacing;

		hwndButton = GetDlgItem(hwnd, IDNO);
		SetWindowText(hwndButton, L"👎");
		MoveWindow(hwndButton, x, 83, cx, 32, TRUE);
		x += cx + spacing;

		hwndButton = GetDlgItem(hwnd, IDCANCEL);
		MoveWindow(hwndButton, x, 83, cx, 32, TRUE);
		SetWindowText(hwndButton, L"🤚");
		return 0;
	}

	return CallNextHookEx(g_hHook, nCode, wParam, lParam);
}

int APIENTRY wWinMain(
	_In_ HINSTANCE hInstance,
	_In_opt_ HINSTANCE /*hPrevInstance*/,
	_In_ PWSTR /*lpCmdLine*/,
	_In_ int /*nCmdShow*/)
{
	HWND hwndParent = NULL;

	g_hHook = SetWindowsHookEx(WH_CBT, HookProc, NULL, GetCurrentThreadId());

	//DialogBox(hInstance, MAKEINTRESOURCE(IDD_ABOUTBOX), hwndParent, AboutProc);
	MessageBox(hwndParent, L"Text", L"Caption", MB_YESNOCANCEL | MB_ICONINFORMATION);


	UnhookWindowsHookEx(g_hHook);
	g_hHook = NULL;

	return 0;
}