Dim Résult As String, i As Integer
For i = 0 To ListBox1.ListCount - 1
If ListBox1.Selected(i) = True Then Résult = Résult & ListBox1.List(i)
Next
For i = 0 To ListBox2.ListCount - 1
If ListBox2.Selected(i) = True Then Résult = Résult & ListBox2.List(i)
Next
Range("A1") = Résult