Removing duplicates from a list box

[claytrainor]

i'm using this code to remove duplicates from a listbox

For i = List1.ListCount - 1 To 1 Step -1
      If List1.List(i) = List1.List(i - 1) Then
          List1.RemoveItem i
        End If
Next i

and it works if the list's are small, but if i have over 1000 entries like i do normally, it doesnt remove duplicates.

any idea?