procedure TfrmSaleHisQry.btnQueryClick(Sender: TObject);
var
    dtpBegin: TDateTimePicker;
    dtpEnd: TDateTimePicker;   
begin
 dtpBegin.Date := StrToDate(FormatDateTime('yyyy/MM/dd',Now())); //时间显示为今天的日期
  dtpEnd.Date := StrToDate(FormatDateTime('yyyy/MM/dd',Now())); //时间显示为今天的日期
  if dtpBegin.Date <= dtpEnd.Date then
  begin
    Messagebox(handle,'查询起始日期<=截止日期','正确',MB_OK);
  end
  else
     Messagebox(handle,'查询起始日期不能大于截止日期','错误',MB_OK);
end;

  if Trunc(dtpBegin.Date) <= Trunc(dtpEnd.Date) then