how to modify DropDownList Size?

I want to redefine the size of DropdownList through below way:

        DropDownList1.Size = 5;

But I got below error messages:
Compiler Error Message: CS1061: 'System.Web.UI.WebControls.ListBox' does not contain a definition for 'Size' and no extension method 'Size' accepting a first argument of type 'System.Web.UI.WebControls.ListBox' could be found (are you missing a using directive or an assembly reference?)

Cannot I modify the dropdownlist size? Can anyone tell me other method to do this?

Thanks a lot.

droupdownlist 没有size这个选项吧。可以通过hight和width去设置其大小。

但是height的单位是px,不好控制. 看来只有在定义listbox时,事先设好Size的值.