delphi - 如何访问汇总字段值作为货币？

Question

当我尝试访问以下行的汇总字段（SUM_TOTAL）的值时：

DM.cdsTOTAL.AsCurrency := DM.cdsItemSUM_TOTAL.AsCurrency;

发生以下错误：

无法访问类型为float的字段“ SUM_TOTAL”。

我的临时解决方案是这样的：

DM.cdsTOTAL.AsCurrency := StrToCurrDef(DM.cdsItemSUM_TOTAL.AsString, 0);

还有其他建议吗？

Answer 1

您可以为TAggregateField实现类帮助器，如果需要，可以为TAggregate实现类帮助器

type
  TAggregateHelper=Class Helper for TAggregate
  private
    function GetCurrency: Currency;
  published
    Property asCurrency:Currency read GetCurrency;
  End;

  TAggregateFieldHelper=Class Helper for TAggregateField
  private
    function GetCurrency: Currency;
  published
    Property asCurrency:Currency read GetCurrency;
  End;


implementation



{ TAggregateHelper }

function TAggregateHelper.GetCurrency: Currency;
begin
  if not VarIsNull(Value) then
     Result := Value
  else Result := Value;
end;
{ TAggregateFieldHelper }

function TAggregateFieldHelper.GetCurrency: Currency;
begin
  if not VarIsNull(Value) then
     Result := Value
  else Result := Value;
end;


procedure TForm1.Button1Click(Sender: TObject);
begin
  Showmessage(FloatToStr(CDSTotal.AsCurrency) + '-' + FloatToStr(CDS.Aggregat[0].asCurrency));
end;