Delphi实现DBGrid全选和反选功能

//全选
procedure TFrameCustSelector.ToolButton1Click(Sender: TObject);
var
  OldCurrent: TBookmark;
begin
  OldCurrent := DBGrid1.DataSource.DataSet.Bookmark;
  DBGrid1.DataSource.DataSet.DisableControls;
  DBGrid1.DataSource.DataSet.First ;
  while not DBGrid1.DataSource.DataSet.Eof do begin
    DBGrid1.SelectedRows.CurrentRowSelected := true;
    DBGrid1.DataSource.DataSet.Next;
  end;
  DBGrid1.DataSource.DataSet.GotoBookmark(OldCurrent);
  DBGrid1.DataSource.DataSet.EnableControls;
end;
//清除全选
procedure TFrameCustSelector.ToolButton2Click(Sender: TObject);
var
  OldCurrent: TBookmark;
begin
  OldCurrent := DBGrid1.DataSource.DataSet.Bookmark;
  DBGrid1.DataSource.DataSet.DisableControls;
  DBGrid1.DataSource.DataSet.First ;
  while not DBGrid1.DataSource.DataSet.Eof do begin
    DBGrid1.SelectedRows.CurrentRowSelected := False;
    DBGrid1.DataSource.DataSet.Next;
  end;
  DBGrid1.DataSource.DataSet.GotoBookmark(OldCurrent);
  DBGrid1.DataSource.DataSet.EnableControls;
end;
//反选
procedure TFrameCustSelector.ToolButton3Click(Sender: TObject);
var
OldCurrent: TBookmark;
begin
  OldCurrent := DBGrid1.DataSource.DataSet.Bookmark;
  DBGrid1.DataSource.DataSet.DisableControls;
  DBGrid1.DataSource.DataSet.First ;
  while not DBGrid1.DataSource.DataSet.Eof do begin
    DBGrid1.SelectedRows.CurrentRowSelected := not DBGrid1.SelectedRows.CurrentRowSelected;
    DBGrid1.DataSource.DataSet.Next;
  end;
  DBGrid1.DataSource.DataSet.GotoBookmark(OldCurrent);
  DBGrid1.DataSource.DataSet.EnableControls;
end;