.Net关闭数据库连接时判断ConnectionState为Open还是Closed？

两种写法：

 if (conn.State == System.Data.ConnectionState.Open)
            {
                conn.Close();
            }

 

 if (conn.State != System.Data.ConnectionState.Closed)
            {
                conn.Close();
            }

大家常用的是哪个？