🚀 go-pugleaf

Hello everyone !

I have problem like this :

void __fastcall TDatModMaintFinPeriods::QryFinPeriodBeforePost(
      TDataSet *DataSet)
{
  if (FrmMaintFinPeriods -> WriteMode == "Insert")
  {
    Finperiod_up(DataSet);
  }
  else
  {
    Finperiod_up(FrmMaintFinPeriods->old_record, DataSet);
  };
}

void __fastcall TDatModMaintFinPeriods::QryFinPeriodBeforeEdit(
      TDataSet *DataSet)
{
FrmMaintFinPeriods->old_record =  DataSet;

};

I want to save old record before editting record to variable old_record, How
should I do because old_record always have the same value with TDataSet
*DataSet, so I can not access the value before editting.

And I have another Question too,

TDataSet *temp = new TDataSet(NULL);

but it trigs a error that says "Cannot create instance of abstract class
'TDataSet'". Why it can be happens ? and if  I try to create variable from
class TQuery, it's working. Anyone could tell me ,please.