This message selects a string in a multiple-selection list box.
| Parameter | Description |
| wParam | Specifies how to set the selection. If the wParam parameter is nonzero, the string is selected and highlighted; if wParam is zero, the highlight is removed and the string is no longer selected. | |
| lParam | The low-order word of the lParam parameter is an index that specifies which string to set. If lParam is –1, the selection is added to or removed from all strings, depending on the value of wParam. |
The return value is LB_ERR if an error occurs.
This message should be used only with multiple-selection list boxes.