Limit Number Of Displayed Items In Html.dropdownlist?

I have a html.dropdownlist on my webpage as follows: <%=Html.DropDownList("MyDropDown", Model.Data, new { @class = "dropdown"})%> I am populating the dropdown with ~80 items. The issue is that when I click the dropdown the list of items is rendered from the top of the screen to the bottom of the screen. How can I set up the dropdownlist so that it only displays a maximum of 20 items when the dropdown menu is clicked (i.e. user needs to scroll down to see items 21 - 80)?

I was anticipating (!) that there would be a html.dropdownlist property to control the number of displayed items that would allow something like the following e.g.: <% =Html.DropDownList("MyDropDown", Model.Data, new { @class = "dropdown", rows ="20"}) %> From research I have been doing on the msdn website it appears that there is no such property and that each browser has its own rules of how many items are displayed in a dropdownlist (?).