winapi - NMHDR 中的 wParam WM_NOTIFY 和 idFrom 有什么区别？

Question

The documentation for WM_NOTIFY says :

• wParam:
  The identifier of the common control sending the message. This identifier is not guaranteed to be unique. An application should use the hwndFrom or idFrom member of the NMHDR structure (passed as the lParam parameter) to identify the control.

And the documentation for NMHDR says :

• idFrom
  An identifier of the control sending the message.

这两者到底有什么区别？

Answer 1

总体来说没有区别。这是一个方便。与在 WM_COMMAND 消息中获得的便利相同，该消息同时传递 ID 和窗口句柄，即使您可以通过 GetDlgCtrlID 从窗口句柄派生 ID。