1、在OnInitDialog中设置：
CRect rectLarge;
CRect rectSmall;
CRect rectSeparate;
GetWindowRect(&rectLarge);
GetDlgItem(IDC_SEPARATE)->GetWindowRect(&rectSeparate);
rectSmall.top = rectLarge.top;
rectSmall.left = rectLarge.left;
rectSmall.right = rectLarge.right;
rectSmall.bottom = rectSeparate.top;
SetWindowPos(NULL,rectSmall.TopLeft().x,rectSmall.TopLeft().y,rectSmall.Width(),rectSmall.Height(),
SWP_NOOWNERZORDER );
m_extendHeight = rectLarge.bottom - rectSmall.bottom;
2、单击事件响应：
void CbbDlg::OnBnClickedButton1()
{
CString str;
if(GetDlgItemText(IDC_BUTTON1,str),str== _T("收缩<<"))
{
SetDlgItemText(IDC_BUTTON1,_T("扩展>>"));
}
else
{
SetDlgItemText(IDC_BUTTON1,_T("收缩<<"));
}
CRect lastCurrentRect;
GetWindowRect(&lastCurrentRect);
CRect currentRect;
currentRect.top = lastCurrentRect.top;
currentRect.left = lastCurrentRect.left;
currentRect.right = lastCurrentRect.right;
if(str==_T("收缩<<"))
{
currentRect.bottom = lastCurrentRect.bottom - m_extendHeight;
/*SetWindowPos(NULL,currentRect.TopLeft().x,currentRect.TopLeft().y,currentRect.Width(),currentRect.Height(),
SWP_NOOWNERZORDER );*/
}
else
{
currentRect.bottom = lastCurrentRect.bottom + m_extendHeight;
}
SetWindowPos(NULL,currentRect.TopLeft().x,currentRect.TopLeft().y,currentRect.Width(),currentRect.Height(),
SWP_NOOWNERZORDER);
}