If you want to automate the process of selecting all items in a multiselect listbox you can use the following code. Changing the Selected property to False will have the opposite effect.
Code:'You may want to verify there is something there 'and communicate the fact to the user Dim lngCount As Long lngCount = Me.ListBoxName.ListCount 'MsgBox lngCount Dim lngItem As Long For lngItem = 0 To lngCount - 1 Me.ListBoxName.Selected(lngItem) = True Next lngItem