Remove Duplicate Lines

I have a list of item codes for a data entry and trying to make a simpel vb app to help remove duplicates like:
The entries are in a multiline textbox
123456789
123449112 <- Orignal
787871213
123449112 <- Duplicate

So it removes only duplicates and keeps at leaste one of each code.

One easy way would be to parse the text line by line, and put it in a ListView (with Sorted set to True). The use this For Next loop:

VB Code:

If List1.ListItems.Count = 0 Then
            Exit Sub
        Else
            J = List1.ListItems.Count
        End If
        
        For I = J To 2 Step -1
            If List1.ListItems.Item(I).Text = List1.ListItems.Item(I - 1).Text Then
                List1.ListItems.Remove J
            End If
        Next I