using (SqlConnection conn = new SqlConnection(Connstring)       {           conn .Open();           // 开启一个事务           SqlTransaction sqlTran = conn .BeginTransaction();           // Enlist a command in the current transaction.           SqlCommand command = conn .CreateCommand();           //begin transaction           command.Transaction = sqlTran;              try           {               // 执行sql语句                command.CommandText ="xxxxx";               command.ExecuteNonQuery();               command.CommandText ="yyyyyy"；               command.ExecuteNonQuery();               // 提交                sqlTran.Commit();           }           catch (Exception ex)           {               // 执行失败回滚操作.               lblMsg.Text = ex.Message;               try               {                   // 回滚.                   sqlTran.Rollback();               }               catch (Exception exRollback)               {                 // 异常                    lblMsg.Text = exRollback.Message;               }           }       }