SDK listbox 自绘的问题

case WM_DRAWITEM:
{
LPDRAWITEMSTRUCT item_ptr=(LPDRAWITEMSTRUCT)lParam;
if (item_ptr->CtlType==ODT_LISTBOX)
{
HDC hdc=item_ptr->hDC;
if (item_ptr->itemID!=(UINT)-1)
{
RECT crc;
GetClientRect(hWnd,&crc);
if (item_ptr->itemState & ODS_SELECTED==ODS_SELECTED || item_ptr->itemAction==ODA_SELECT)
{
FrameRect(hdc,&item_ptr->rcItem,br_sel);
}
if (item_ptr->itemState & ODS_FOCUS==ODS_FOCUS && item_ptr->itemAction==ODA_FOCUS)
{

}
btm_old=crc.bottom;
crc.bottom=item_ptr->rcItem.top;
FillRect(hdc,&crc,br_bg);
crc.top=item_ptr->rcItem.bottom;
crc.bottom=btm_old-item_ptr->rcItem.bottom;
FillRect(hdc,&crc,br_bg);
SetBkMode(hdc,TRANSPARENT);
char sztext[255]={0};
SendMessage(listctrl,LB_GETTEXT,item_ptr->itemID,(LPARAM)(LPTSTR)sztext);
DrawText(hdc, sztext, strlen(sztext), &item_ptr->rcItem,DT_LEFT | DT_SINGLELINE); 
}
}
}
怎么绘制没有选中的？SDKListBox自绘