net C# DateTime ToString 格式化
DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss:ffff"); // => 2016-05-09 13:09:55:2350
DateTime.Now.ToString("yyyy/MM/dd HH:mm:ss:ffff"); // => 2016/05/09 13:09:55:2350
DateTime.Now.ToString("yyyy/MM/dd HH:mm:ss:ffff dddd"); // => 2016/05/09 13:09:55:2350 星期一