Combo box to upper case

Question

I would like to have the characters in a combo box converted to upper case as the user types them. So for instance, when a user types 'a' in the text area, it would be converted to 'A'.

I've tried:

private void cmbList_KeyDown(object sender, KeyEventArgs e)
{
cmbList.Text.ToUpper();
}

Also, is there a way to have the drop down list 'drop' when any character is entered in the text area?