How to sort the sequence of checkbox

I have two checkboxes. If I check cb1 first and cb2 next, the ListBox should display the data of the checkboxes in order of checked sequence.

Public Class Form1

  Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
    If cb1.Checked = True And cb2.Checked = False Then
      ListBox1.Items.Add(cb1.Text)
      If cb1.Checked = True And cb2.Checked = True Then
        ListBox1.Items.Add(cb1.Text)
      End If
    ElseIf cb2.Checked = True And cb1.Checked = False Then
      ListBox1.Items.Add(cb2.Text)
      If cb2.Checked = True And cb1.Checked = True Then
        ListBox1.Items.Add(cb1.Text)
      End If
    End If
  End Sub
End Class

If only one checkbox is checked it displays the data, but if both are checked there's no data displayed in the list box.