MFC 全屏后 combo box 中没有内容

如题float fsp[2];
POINT Newp; //获取现在对话框的大小
CRect recta;   
GetClientRect(&recta); //取客户区大小   
Newp.x=recta.right-recta.left;
Newp.y=recta.bottom-recta.top;
fsp[0]=(float)Newp.x/Old.x;
fsp[1]=(float)Newp.y/Old.y;
CRect Rect;
int woc;
CPoint OldTLPoint,TLPoint; //左上角
CPoint OldBRPoint,BRPoint; //右下角
HWND hwndChild=::GetWindow(m_hWnd,GW_CHILD); //列出所有控件   
while(hwndChild)   
{   
woc=::GetDlgCtrlID(hwndChild);//取得ID
GetDlgItem(woc)->GetWindowRect(Rect);   
ScreenToClient(Rect);   
OldTLPoint = Rect.TopLeft();   
TLPoint.x = long(OldTLPoint.x*fsp[0]);   
TLPoint.y = long(OldTLPoint.y*fsp[1]);   
OldBRPoint = Rect.BottomRight();   
BRPoint.x = long(OldBRPoint.x *fsp[0]); 
if (woc != 1128)
{
BRPoint.y = long(OldBRPoint.y *fsp[1]); //高度不可读的控件（如:combBox),不要改变此值.
}

if (woc == 1 || woc == 2)
{
long x = TLPoint.x+Rect.right-Rect.left;
long y = TLPoint.y+Rect.bottom-Rect.top; TLPoint.x = BRPoint.x - x + TLPoint.x;
BRPoint.y = y;
}
Rect.SetRect(TLPoint,BRPoint);   
GetDlgItem(woc)->MoveWindow(Rect,TRUE);
hwndChild=::GetWindow(hwndChild, GW_HWNDNEXT);   
}
Old=Newp;