如何显示CListBox的水平滚动条？

[itti]

请问高手：
如何显示CListBox的水平滚动条？在属性框中选中"Horizontal scroll"，即使显示内容超出控件宽度，仍不显示水平滚动条，为什么？谢谢！

[bmon_xyz]

需要手动编程，MSDN上的例子：
// The pointer to my list box.
extern CListBox* pmyListBox;

// Find the longest string in the list box.
CString str;
CSize sz;
int dx = 0;
TEXTMETRIC tm;
CDC* pDC = pmyListBox->GetDC();
CFont* pFont = pmyListBox->GetFont();

// Select the listbox font, save the old font
CFont* pOldFont = pDC->SelectObject(pFont);
// Get the text metrics for avg char width
pDC->GetTextMetrics(&tm);

for (int i = 0; i < pmyListBox->GetCount(); i++)
{
pmyListBox->GetText(i, str);
sz = pDC->GetTextExtent(str);

// Add the avg width to prevent clipping
sz.cx += tm.tmAveCharWidth;

if (sz.cx > dx)
dx = sz.cx;
}
// Select the old font back into the DC
pDC->SelectObject(pOldFont);
pmyListBox->ReleaseDC(pDC);

// Set the horizontal extent so every character of all strings
// can be scrolled to.
pmyListBox->SetHorizontalExtent(dx);