Delphi 关于DBGrid多选删除(shitf多选，ctrl多选)

////删除多选记录

procedure THistoryForm.DeleteButtonClick(Sender: TObject);
var
  tempBookMark:TbookMark;
  i:integer;
begin
  if dbgrid1.SelectedRows.Count <= 0 Then
  begin
    MessageBox(Handle,'请选择您要删除的记录','提示',MB_OK);
    Exit;
  end;

  If MessageBox(Handle,'删除后数据将不可恢复，您确定要删除吗？','提示',mb_iconinformation+mb_YesNo)=IdYes Then
  Begin
    i:=0;
    DBGrid1.Datasource.Dataset.DisableControls;
    While i<=dbgrid1.SelectedRows.Count - 1 Do
    Begin
      DBGrid1.Datasource.Dataset.Bookmark:=dbgrid1.SelectedRows.Items[i];//重要的在这里,取得BOOKMARK
      TempBookmark:=DBGrid1.Datasource.Dataset.GetBookmark;
      DBGrid1.Datasource.Dataset.GotoBookmark(TempBookmark);

      with ADOQuery3 do
      begin
        Close;
        SQL.Clear;
        SQL.Add('delete from his where id=:a');
       Parameters.ParamByName('a').Value:=Dbgrid1.DataSource.DataSet.fieldbyname('id').AsInteger;
        ExecSql;
      end;
      DBGrid1.Datasource.Dataset.FreeBookmark(TempBookmark);     //释放BOOKMARK
      inc(i);   //下一个选择记录
    End;
    DBGrid1.Datasource.Dataset.EnableControls;
    Act_ShowCTInfo(LBName.Caption);
    Memo1.Clear;
  end;
end;

//定义全局变量

var

  blSelect: Boolean;
  BookMark: TBookMark;
  CurrNo, OldNo: integer;

/////////按Shift多选

procedure THistoryForm.DBGrid1MouseUp(Sender: TObject;
  Button: TMouseButton; Shift: TShiftState; X, Y: Integer);
begin //实现 Shift+鼠标左键单击 多选
  if Button = mbLeft then
  begin
    if not blSelect then
    begin
      BookMark := ADOQuery1.GetBookMark;
      OldNo := ADOQuery1.RecNo;
      blSelect := True;
      Exit;
    end
    else
    begin
      if ssShift in Shift then
      begin
        CurrNo := ADOQuery1.RecNo;
        ADOQuery1.DisableControls;
        ADOQuery1.GotoBookmark(BookMark);
        DBGrid1.SelectedRows.CurrentRowSelected := True;
        if CurrNo > OldNo then
        begin
          while CurrNo > ADOQuery1.RecNo do
          begin
            DBGrid1.SelectedRows.CurrentRowSelected := True;
            ADOQuery1.Next;
          end;
        end
        else
        begin
          while CurrNo < ADOQuery1.RecNo do
          begin
            DBGrid1.SelectedRows.CurrentRowSelected := True;
            ADOQuery1.Prior;
          end;
        end;
        ADOQuery1.EnableControls;
        ADOQuery1.FreeBookmark(BookMark);
        blSelect := False;
        CurrNo := 0;
        OldNo := 0;
      end
      else
      begin
        BookMark := ADOQuery1.GetBookMark;
        OldNo := ADOQuery1.RecNo;
        blSelect := True;
        Exit;
      end;
    end;
  end;
end;