SetWinEventHook

[DllImport("user32.dll", SetLastError = true)]
public static extern IntPtr SetWinEventHook(
   uint eventMin,
   uint eventMax,
   IntPtr hmodWinEventProc,
   WinEventProc pfnWinEventProc,
   uint idProcess,
   uint idThread,
   uint dwFlags
);

Microsoft documentation: Link