IndexFromPoint for Combobox ?

Question

Hi!

If i do this
private void listBox1_MouseMove(object sender, MouseEventArgs e)

{label1.Text = listBox1.IndexFromPoint(e.X, e.Y).ToString();}

the label displays the index of the item where my mouse is at the moment
How do i get the same result in a ComboBox?
it dosent have that method, and when i click the dropdown button of the ComboBox it loses Focus and a Listbox is displayed, how do i access that list event ?

Note:i dont want to know the index after it is clicked, i want to know the index as my mouse is moving through the list.

thanks in advance for a response.