The EN_CHANGE notification message is sent when the user has taken an action that may have altered text in an edit control. Unlike the EN_UPDATE notification message, this notification message is sent after Windows updates the screen. The parent window of the edit control receives this notification message through the WM_COMMAND message.
EN_CHANGE idEditCtrl = (int) LOWORD(wParam); // identifier of edit control hwndEditCtrl = (HWND) lParam; // handle of edit control