Centering MessageBox << Back

It all stemmed from this post. The good thing is that there is an article on CodeProject shows you how to do that. The following code is basically a bit updated code that has the following improvements

• It's in C++. No need for .NET runtime libraries
• Take Multiple Monitor into consideration.
• You can leave the hook up there instead of hooking/unhooking before calling MessageBox.
• Take Workarea into consideration so that the message box doesn't show up behind the taskbar.

#include <windows.h>

HHOOK ghHook;

void CenterMessageBox(HWND hOwner, HWND hMsgBox)
{
	RECT rOwner, rMsgBox;
	MONITORINFO mi;
	GetWindowRect(hOwner, &rOwner);
	HMONITOR hMon = MonitorFromWindow(hOwner, MONITOR_DEFAULTTONEAREST);
	mi.cbSize = sizeof(mi);
	GetMonitorInfo(hMon, &mi);
	GetWindowRect(hMsgBox, &rMsgBox);
	int iWidth = rMsgBox.right - rMsgBox.left;
	int iHeight = rMsgBox.bottom - rMsgBox.top;
	int ix = ((rOwner.right - rOwner.left) - iWidth) / 2;
	int iy = ((rOwner.bottom - rOwner.top) - iHeight) / 2;
	int iLeft = rOwner.left + ix;
	int iTop = rOwner.top + iy;
	int iRight = iLeft + iWidth;
	int iBottom = iTop + iHeight;
	if (iRight >= mi.rcWork.right) iLeft = mi.rcWork.right - iWidth;
	if (iBottom >= mi.rcWork.bottom) iTop = mi.rcWork.bottom - iHeight;
	if (iLeft < mi.rcWork.left) iLeft = mi.rcWork.left;
	if (iTop < mi.rcWork.top) iTop = mi.rcWork.top;
	SetWindowPos(hMsgBox, NULL, iLeft, iTop, 0, 0, SWP_NOACTIVATE | SWP_NOZORDER | SWP_NOSIZE);
}

LRESULT CALLBACK HookProc(_In_ int nCode, _In_ WPARAM wParam, _In_ LPARAM lParam)
{
	TCHAR szClass[8];
	HWND hMsgBox;
	LRESULT lResult = CallNextHookEx(ghHook, nCode, wParam, lParam);
	if (nCode == HCBT_ACTIVATE)
	{
		hMsgBox = reinterpret_cast<HWND>(wParam);
		if (!IsWindowVisible(hMsgBox))
		{
			if (GetClassName(hMsgBox, szClass, 8))
			{
				if (lstrcmp(szClass, TEXT("#32770")) == 0) // You can do more checks to see if it is really a message box.
				{
					HWND hOwner = GetWindow(hMsgBox, GW_OWNER);
					if (hOwner)
						CenterMessageBox(hOwner, hMsgBox);
				}
			}
		}
	}
	return lResult;
}

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