EN_KILLFOCUS    
The
EN_KILLFOCUS notification message is sent when an edit control loses the
keyboard focus. The parent window of the edit control receives this
notification message through the WM_COMMAND message. 
EN_KILLFOCUS 
idEditCtrl = (int) LOWORD(wParam); // identifier of
edit control 
wNotifyCode = HIWORD(wParam);      // notification code 
hwndEditCtrl = (HWND) lParam;      // handle of edit control 
 
Remarks
In previous
versions of Windows, the notification code was in HIWORD(lParam).
See Also