MFC 的CCombox的SetHorizontalExtent这个函数是不是没有作用

Question

我想实现combox里面的list有一个横的滚动条，但是SetHorizontalExtent貌似没有作用
，msdn文档明明写着它的作用：
If the width of the list box is smaller than this value, the horizontal scroll bar will horizontally scroll items in the list box. If the width of the list box is equal to or greater than this value, the horizontal scroll bar is hidden or, if the combo box has the CBS_DISABLENOSCROLL style, disabled.

但事实是没有任何卵用
这是为啥
有谁可以给出一个方案帮我解决一下吗~

Answer 1

写着它的作用：
If the width of the list box is smaller than this value, the horizontal scroll bar will horizontally scroll items in the list box. If the width of the list box is equal to or greater than this value, the horizontal scroll bar is hidden or, if the combo box has the CBS_DISABLENOSCROLL style, disabled.
但事实是没有任何卵用
这是为啥
有谁可以给出一个方案