The EN_UPDATE notification message is sent when an edit control is about to display altered text. This notification message is sent after the control has formatted the text, but before it displays the text. This makes it possible to resize the edit control window, if necessary. The parent window of the edit control receives this notification message through the WM_COMMAND message.
EN_UPDATE
idEditCtrl = (int) LOWORD(wParam); // identifier of edit control
hwndEditCtrl = (HWND) lParam; // handle of edit control
See Also