Ok, George, the simplest way is the following. But, if you have a huge number of entries in the listbox it may bog down.....

** Listbox.InterActiveChange code
ThisForm.cmdButton.Refresh()
****

** cmdButton.Refresh
nSelCount=0
lEnabled=.F.
FOR i = 1 TO ThisForm.Listbox.ListCount
   IF ThisForm.Listbox.Selected(i)
      nSelCount=nSelCount+1
      IF nSelCount >= 2
         lEnabled=.T.
      ENDIF
   ENDIF
ENDFOR
This.Enabled=lEnabled

>Hi, all!
>
>Here is my problem:
>
>I have a multiselect listbox on a form. There is also a command button on the form. The command button should only be enabled if two or more list items are selected.
>
>Is there any event which fires as list items are selected/unselected?
>
>I tried putting some code in the mousedown/mouseup events. This works unless the user uses the keyboard to select items.
>
>I also tried creating a custom listbox class, with a selected_assign() method. This method doesn't seem to ever fire. I was hoping that as the selected() property of the listbox changed, the assign method would fire. But it doesn't.
>
>Any ideas?
>
>- George