Showing Win32 common dialog at desktop center from a console program [duplicate] - c++

Question

This is my attempt using a hook function to get the dialog window handle. Both SetWindowPos() and GetLastError() return correct values, but the dialog window is unaffected and shown at position 0,0.
#include <windows.h>
#include <iostream>
static UINT_PTR CALLBACK OFNHookProc (HWND hdlg, UINT uiMsg, WPARAM wParam, LPARAM lParam) {
using namespace std;
switch (uiMsg) {
case WM_INITDIALOG: {
// SetWindowPos returns 1
cout << SetWindowPos(hdlg, HWND_TOPMOST, 200, 200, 0, 0, SWP_NOSIZE ) << endl;
// GetLastError returns 0
cout << GetLastError() << endl;
break;
}
}
return 0;
}
int main() {
OPENFILENAMEW ofn;
ZeroMemory(&ofn, sizeof(ofn));
ofn.lStructSize = sizeof(OPENFILENAMEW);
ofn.nMaxFile = MAX_PATH;
ofn.Flags = OFN_EXPLORER | OFN_FILEMUSTEXIST | OFN_ENABLEHOOK;
ofn.lpfnHook = OFNHookProc;
GetOpenFileNameW(&ofn);
return 0;
}

Answer 1

When using OFN_EXPLORER, you have to move hdlg's parent window, as the HWND passed to your callback is not the actual dialog window. This is clearly stated in the documentation:
OFNHookProc callback function
hdlg [in]
A handle to the child dialog box of the Open or Save As dialog box. Use the GetParent function to get the handle to the Open or Save As dialog box.
Also, you should wait for the callback to receive the CDN_INITDONE notification, instead of the WM_INITDIALOG message.
Try this:
static UINT_PTR CALLBACK OFNHookProc (HWND hdlg, UINT uiMsg, WPARAM wParam, LPARAM lParam)
{
if ((uiMsg == WM_NOTIFY) &&
(reinterpret_cast<OFNOTIFY*>(lParam)->hdr.code == CDN_INITDONE))
{
SetWindowPos(GetParent(hdlg), HWND_TOPMOST, 200, 200, 0, 0, SWP_NOSIZE);
}
return 0;
}