Private Sub File1_Click()
  Dim sPDFDoc As String
 
  With File1
    If .ListIndex > -1 Then
      sPDFDoc = File1.Path & _
        IIf(Right$(sPDFDoc, 1) <> "\", "\", "") & _
        .List(.ListIndex)
 
      PDF1.src = sPDFDoc
    End If
  End With
End Sub