/// <summary>
 /// 删除命令
 /// </summary>
 /// <returns></returns>
 public override void ExecuteDelete()
 {
     if (SelectedSystem != null)
     {
         SystemInfoBLL bll = new SystemInfoBLL();
         if (bll.DeleteSystemInfo(SelectedSystem))
         {
             SystemList.Remove(SelectedSystem);
             SelectedSystem = null;
         }
     }
 }