Как связать DirListBox1 и ComboBox1 - VB

Private Sub Command1_Click()
t1 = Dir1.List(-1)
t2 = Len(Dir1.List(-2)) + 1
If t2 > 4 Then t2 = t2 + 1
Text1 = Mid(t1, t2, Len(t1))
End Sub