This code specifies that the user has clicked the edit control's horizontal scroll bar. The control's parent window receives this code through a WM_COMMAND message from the control. The parent window is notified before the screen is updated.
| Parameter | Description |
| wParam | Contains the wParam parameter of the WM_COMMAND message, and specifies the control ID. | |
| lParam | Contains an edit-control window handle in its low-order word and the EN_HSCROLL code in its high-order word. |