sqlserver 数据库连接状态判断

        /// <summary>
        /// 打开数据库
        /// </summary>
        public void OpenCon()
        {
           if(conn.State!=ConnectionState.Open)
            conn.Open();
        }
        /// <summary>
        /// 关闭数据库
        /// </summary>
        public void CloseCon()
        {
            if(conn.State!=ConnectionState.Closed)
            conn.Close();
        }