C++ Set window below (or above) the icons on the desktop

Question

I'm trying to place a window either above or below the icons on the desktop. I mostly just want it to stay attached to the desktop at all times. Similar to Rainmeter or Wallpaper engine. So far, everything I tried either disables interaction, or gets minimized when you use the "Show Desktop" button. Any ideas on how to achieve this? I'm using electron and a native module in node to do this.

Answer 1

It's an old subject, but I'll find out how to do it recently and answer it.

The method is to find the handle of SHELLDLL_DefView, the parent of the desktop window, and then make the SHELLDLL_DefView handle the parent of my window to fix it to the desktop.

The method is to find the handle of SHELLDLL_DefView, the owner of the desktop window, and then make the SHELLDLL_DefView handle the owner of my window to fix it to the desktop.

SHELLDLL_DefView is located under the Progma or WorkerW handle. This is a code to prevent ShowDesktop from being used in the Electget package created by ffi-napi to attach the Electron browserWindow to the desktop.

const GWLP_HWNDPARENT = -8;

// find SHELLDLL_DefView in Progma
const progman = user32.FindWindowExA(ref.NULL, ref.NULL, 'Progman', ref.NULL);
let defView = user32.FindWindowExA(progman, ref.NULL, 'SHELLDLL_DefView', ref.NULL ); 

// find SHELLDLL_DefView in WorkerW    
if (!defView) {
  const desktopHWnd = user32.GetDesktopWindow();
  let workerW = 0;
  do {
    workerW = user32.FindWindowExA(desktopHWnd, workerW, 'WorkerW', ref.NULL); 
    defView = user32.FindWindowExA(workerW, ref.NULL, 'SHELLDLL_DefView', ref.NULL );
  } while (!defView && workerW);
}

if (!defView) return false;

// make the SHELLDLL_DefView handle the parent of my window
user32.SetWindowLongPtrA(hWnd, GWLP_HWNDPARENT, defView);

This allows you to create a window where you can click and interact without being hidden by ShowDesktop.

---

2022-03-29

There was a wrong word, so I corrected it. According to doc, it is not a parent window, but an owner window. In the doc, it is strange that the GWLP_HWNDPARENT constant is related to the parent window. However, when tested with Spy++, the corresponding constant changes the owner window.