combobox 水平滚动条,该如何解决

combobox 水平滚动条
我用下面的方法实现了添加滚动条，但是，却滚动不了，实现不了滚动功能。为什么啊？？？急急急！！！

CWnd *pWnd= FindWindow("ComboLBox", NULL); 
if(pWnd)  
pWnd->ShowScrollBar(SB_BOTH,true);

[解决办法]

[解决办法]
是要设置吧，在OninitUpdate（）函数里设置
好像是setScroll（）吧
[解决办法]

C/C++ code

BOOL ShowScrollBar(  HWND hWnd,  // handle to window with scroll bar  int wBar,   // scroll bar flag  BOOL bShow  // scroll bar visibility flag); ParametershWnd Handle to a scroll bar control or a window with a standard scroll bar, depending on the value of the wBar parameter. wBar Specifies the scroll bar(s) to be shown or hidden. This parameter can be one of the following values: Value Meaning SB_BOTH Shows or hides a window's standard horizontal and vertical scroll bars. SB_CTL Shows or hides a scroll bar control. The hWnd parameter must be the handle to the scroll bar control. SB_HORZ Shows or hides a window's standard horizontal scroll bars. SB_VERT Shows or hides a window's standard vertical scroll bar. bShow Specifies whether the scroll bar is shown or hidden. If this parameter is TRUE, the scroll bar is shown; otherwise, it is hidden.