procedure Export(Grid: tDBGrid);
var
  SaveBeforeScroll: TDataSetNotifyEvent;
  SaveAfterScroll: TDataSetNotifyEvent;
  SaveAutoCalcFields: Boolean;
begin
  with Grid.Datasource.DataSet do
    begin
      DisableControls;
      SaveBeforeScroll := BeforeScroll;
      SaveAfterScroll := AfterScroll;
      SaveAutoCalcFields := AutoCalcFields;
      BeforeScroll := nil;
      AfterScroll := nil;
      AutoCalcFields := False;

      //Экспортируем куда нужно
      First;
      while not(eof) do
        begin
          next;
        end;

      EnableControls;
      BeforeScroll := SaveBeforeScroll;
      AfterScroll := SaveAfterScroll;
      AutoCalcFields := SaveAutoCalcFields;
    end;
end;

procedure Export(Grid: tDBGrid);
var
  SaveAutoCalcFields: Boolean;
  BM: TBookmark;
begin
  with Grid.Datasource.DataSet do
    begin
      BM := GetBookmark;
      DisableControls;     
      SaveAutoCalcFields := AutoCalcFields;
      BeforeScroll := nil;
      AfterScroll := nil;
      AutoCalcFields := False;

      //Экспортируем куда нужно
      First;
      while not(eof) do
        begin
          next;
        end;

      GotoBookmark(BM);
      EnableControls; 
      AutoCalcFields := SaveAutoCalcFields;
    end;
end;

TDatasetDisable = class(tObject)
      fSaveBeforeScroll: TDataSetNotifyEvent;
      fSaveAfterScroll: TDataSetNotifyEvent;
      fSaveAutoCalcFields: Boolean;
      fdataset: tDataset;
      fBookMark: tBookMark;
    public
      constructor Create(aDataset: tDataset);
      destructor destroy; override;
  end;

constructor TDatasetDisable.Create(aDataset: tDataset);
begin
  inherited Create();
  fDataset := aDataset;
  if assigned(fDataset) then
    begin
      fSaveBeforeScroll := fDataSet.BeforeScroll;
      fSaveAfterScroll  := fDataSet.AfterScroll;
      fSaveAutoCalcFields := false;
      fBookMark := fDataSet.BookMark;
      fDataSet.DisableControls;
      fDataSet.BeforeScroll := nil;
      fDataSet.AfterScroll := nil;
      fDataSet.AutoCalcFields := False;

    end;
end;

destructor TDatasetDisable.Destroy;
begin
  if assigned(fDataset) then
    begin
      fDataSet.EnableControls;
      fDataSet.BeforeScroll := fSaveBeforeScroll;
      fDataSet.AfterScroll := fSaveAfterScroll;
      fDataSet.AutoCalcFields := fSaveAutoCalcFields;
      fDataSet.GotoBookMark(fBookmark);
    end;
  inherited;
end;

procedure Export(Grid: tDBGrid);
var
  SetDatasetDisable := TDatasetDisable;	
begin
 SetDatasetDisable := TDatasetDisable.create(Grid.DataSource.DataSet);
 if (Grid.SelectedRows <> nil) and (Grid.SelectedRows.Count > 0)  then
 for i := 0 to Grid.SelectedRows.Count - 1 do
   begin
     //экспортируем строку               
   end
 else
   begin
     Grid.DataSource.DataSet.First;
     while not Grid.DataSource.DataSet.Eof do
       begin
         //экспортируем строку               
         Grid.DataSource.DataSet.Next;
       end;
    end;
 SetDatasetDisable.free;
end;