void del( )
 {
     result = _bll.Delete(_dc.DC001, Logins.username);
     if (result)
     {
         MessageBox.Show("删除成功");
         UnEnable( );
         Clear( );
         toolSelect.Enabled = toolAdd.Enabled = true;
         toolSave.Enabled   = toolCancel.Enabled = toolDelete.Enabled = toolUpdate.Enabled = toolReview.Enabled = toolPrint.Enabled = toolExport.Enabled = toolMaintain.Enabled = toolcopy.Enabled = toolLibrary.Enabled = toolStorage.Enabled = false;
     }
     else
     {
         MessageBox.Show("删除失败,请重试");
     }
 }