Niečo takéto?

Private Sub listBox1_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles listBox1.SelectedIndexChanged
   ' Get the currently selected item in the ListBox. 
   Dim curItem As String = listBox1.SelectedItem.ToString()
   if curItem = "strom"
     MessageBox.Show("Klikol si na strom")
End Sub