DbTransaction tran = _dataContext.Transaction

 if (_dataContext.Connection.State == System.Data.ConnectionState.Closed)
                _dataContext.Connection.Open();
            else
            {
                _dataContext.Connection.Close();
                _dataContext.Connection.Open();
            }
            //DbTransaction tran = _dataContext.Transaction = _dataContext.Connection.BeginTransaction();
            //_dataContext.Transaction = tran;
            //try
            //{
                
               
            //    _dataContext.SubmitChanges();
            //    //添加凭证信息
 
            //    tran.Commit();
                
            //}
            //catch
            //{
            //    tran.Rollback();
            //    return false;
            //}