C# 展示过去了多长时间的函数

public string HowLongBeforeNow        {            get            {                var ts = new TimeSpan(DateTime.UtcNow.Ticks - CreatedDate.Ticks);                var delta = ts.TotalSeconds;                const int second = 1;                const int minute = 60 * second;                const int hour = 60 * minute;                const int day = 24 * hour;                const int month = 30 * day;                if (delta < 0)                {                    throw new InvalidDataException("The CreatedDate can not be gather than today.");                }                if (delta < 1 * minute)                {                    return ts.Seconds == 1 ? "1 second ago" : ts.Seconds + " seconds ago";                }                if (delta < 2 * minute)                {                    return "1 minute ago";                }                if (delta < 45 * minute)                {                    return ts.Minutes + " minutes ago";                }                if (delta < 90 * minute)                {                    return "1 hour ago";                }                if (delta < 24 * hour)                {                    return ts.Hours + " hours ago";                }                if (delta < 48 * hour)                {                    return "yesterday";                }                if (delta < 30 * day)                {                    return ts.Days + " days ago";                }                if (delta < 12 * month)                {                    var months = Convert.ToInt32(Math.Floor((double)ts.Days / 30));                    return months <= 1 ? "1 month ago" : months + " months ago";                }                var years = Convert.ToInt32(Math.Floor((double)ts.Days / 365));                return years <= 1 ? "1 year ago" : years + " years ago";            }        }

.how-long-ago {        font-style: italic;        color: #777;    }