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 display. The control's parent window receives this notification message through a WM_COMMAND message.
wParam
Specifies the identifier of the edit control.
lParam
Specifies the handle of the edit control in the low-order word, and specifies the EN_CHANGE notification message in the high-order word.