SetFocus SetActiveWindow 被设置的对象需要为设置的孩子等

SetFocus

SetFocus([in] HWND hWnd)
// If the function succeeds, the return value is the handle to the window that previously had the keyboard focus. If the hWnd parameter is invalid or the
// window is not attached to the calling thread's message queue, the return value is NULL.

SetActiveWindow

SetActiveWindow([in] HWND hWnd )
// Activates a window. The window must be attached to the calling thread's message queue.
// If the function succeeds, the return value is the handle to the window that was previously active.
// If the function fails, the return value is NULL.

SetCapture

HWND SetCapture(
  [in] HWND hWnd
);