Another option is to provide a checkbox with each item. See http://support.microsoft.com/kb/157048/en-us

>Hi all,
>In the click event, how can I tell the difference between
>CTRL+Click and just Click (w/o CTRL)?
>
>And was wondering if I could have multiple different functionality
>"Shift+Click to multiselect for this purpose.."
>"CTRL+Click to multiselect for that purpose.."
>Thanks