新建一 DataSet , 并加入数据 : prepareTable
function TFrm_Print.CreateTableInMemory(const AFieldDefs:TFieldDefs):TDataSet;
var
  TempTable:TClientDataSet;
begin
  TempTable:=nil;
  Result:=nil;
  if AFieldDefs<>nil then
  begin
    try
      TempTable:=TClientDataSet.Create(Application);
      TempTable.FieldDefs.Assign(AFieldDefs);
      TempTable.CreateDataSet;
      Result:=(TempTable as TDataSet);
    Except
      if TempTable<>nil then
      TempTable.Free;
      raise;
    end
  end;
end;

procedure TFrm_Print.CreateDataSet(var gDataSet:Tdataset);
var ADataSet:TDataSet;
begin
  try
    if assigned(gDataSet) then gDataSet.free;
  except
  end;
    ADataSet:=TDataSet.Create(Self);
    try
      with ADataSet.FieldDefs do
      begin
        add('OrderNo',ftInteger);
        add('prjName',ftString,200);
        add('srcPrice',ftFloat);
      end;
      gDataSet:=CreateTableInMemory(ADataSet.FieldDefs);
      gDataSet.Open;
    finally
    ADataSet.Free;
    end;
end;

procedure Tfrm_GoodsMg.prepareTable(var gDataSet:Tdataset);
  procedure prepareDataSet;
  begin
{   while not 数据源.eof do begin
      gDataSet.append;
      gDataSet.fieldbyname('OrderNo').asInteger:= I_Value;
      gDataSet.fieldbyname('prjName').asString := A_Value;
      gDataSet.fieldbyname('OrderNo').asFloat  := D_value;
      gDataSet.post;
      数据源.next;
    end;            }
  end;
begin
    CreateDataSet(gDataSet);
    prepareDataSet;
end;

procedure getMyDataSet()
var myDataSet:Tdataset
begin
    prepareTable(myDataSet); 
    myDataSet.free;
end;