用C表示时间(不是日期和时间)#

我个人会使用时间跨度而不是日期时间,但我听说其他人表达了相反的观点。

[Serializable()]
public class OpeningTime
{
    protected OpeningTime()
    {
    }

    public OpeningTime(DayOfWeek dayOfWeek, TimeSpan fromTime, TimeSpan toTime) 
        : this(dayOfWeek, fromTime.Hours, fromTime.Minutes, toTime.Hours, toTime.Minutes) { }

    public OpeningTime(DayOfWeek dayOfWeek, int fromHours, int fromMinutes, int toHours, int toMinutes)
    {
        if (fromHours < 0 || fromHours > 23)
        {
            throw new ArgumentOutOfRangeException("fromHours", "fromHours must be in the range 0 to 23 inclusive");
        }

        if (toHours < 0 || toHours > 23)
        {
            throw new ArgumentOutOfRangeException("toHours", "toHours must be in the range 0 to 23 inclusive");
        }

        if (fromMinutes < 0 || fromMinutes > 59)
        {
            throw new ArgumentOutOfRangeException("fromMinutes", "fromMinutes must be in the range 0 to 59 inclusive");
        }

        if (toMinutes < 0 || toMinutes > 59)
        {
            throw new ArgumentOutOfRangeException("toMinutes", "toMinutes must be in the range 0 to 59 inclusive");
        }

        this.FromTime = new TimeSpan(fromHours, fromMinutes, 0);
        this.ToTime = new TimeSpan(toHours, toMinutes, 0);

        if (this.FromTime >= this.ToTime)
        {
            throw new ArgumentException("From Time must be before To Time");
        }

        this.DayOfWeek = dayOfWeek;
    }

    public virtual DayOfWeek DayOfWeek { get; private set; }

    public virtual TimeSpan FromTime { get; private set; }

    public virtual TimeSpan ToTime { get; private set; }
}

坚持使用日期时间

我只会使用datetime,因为它很好地映射到SQL(SQL也使用datetime),而且我发现它比使用TimeSpan更可读。例如,您还可以使用同一个对象并向其添加日期以获取今天的开始时间。

为什么不是时间跨度?

因为它的名字是真的,这意味着什么。TimeSpan表示一段时间,而不是一个时间点。虽然它在框架中被用来表示精确的时间(在time-ofday中),但该属性是被定义的 in the docs AS:

表示从午夜开始一天中所经过的时间段。

但是…其实没什么关系

最后,它没有什么区别,您可以使用TimeSpan、DateTime或您自己的结构。这两者的开销都很小,归根结底就是您发现更易于阅读和维护的内容。

你可以使用 TimeSpan 代表一天中的某个时间。

我认为您可以在内部将其表示为开始的日期时间(它为dayOfWeek),然后表示结束的时间跨度,但将它们公开为日期时间或时间跨度三个属性。

现在打开更多的DDD帽子…您可以使用TimeSpan对象来表示一天中的某个时间,但是如果我按照DDD术语进行思考,我会想知道商店什么时候开门。时间跨度可以代表更多信息的方式,每次与它们打交道时,您必须具体验证它们的长度不超过一天。

因此,一种方法是创建一个简单的类来表示您试图表示的内容(您可以只包装一个时间跨度对象,而不是使用几个整数)。

public struct Time 
{
    private readonly int _hour;
    private readonly int _minute;
    private readonly int _second;

    public Time(int hour, int minute, int second)
    {
        if (hour < 0 || hour >= 24)
            throw new ArgumentOutOfRangeException("hour", "Hours must be between 0 and 23 inclusive");
        if (minute < 0 || minute > 59)
            throw new ArgumentOutOfRangeException("minute", "Minutes must be between 0 and 23 inclusive");
        if (second < 0 || second > 59)
            throw new ArgumentOutOfRangeException("second", "Seconds must be between 0 and 23 inclusive");
        _hour = hour;
        _minute = minute;
        _second = second;
    }

    public Time(Time time)
        : this(time.Hour, time.Minute, time.Second)
    {

    }

    public int Hour { get { return _hour; } }
    public int Minute { get { return _minute; } }
    public int Second { get { return _second; } }

    public override string ToString()
    {
        return ToString(true);
    }

    public string ToString(bool showSeconds)
    {
        if (showSeconds)
            return string.Format("{0:00}:{1:00}:{2:00}", Hour, Minute, Second);
        return string.Format("{0:00}:{1:00}:{2:00}", Hour, Minute);
    }

    public override bool Equals(object obj)
    {
        if (ReferenceEquals(null, obj)) return false;
        if (obj.GetType() != typeof (Time)) return false;
        return Equals((Time) obj);
    }

    public bool Equals(Time other)
    {
        return other._hour == _hour && other._minute == _minute && other._second == _second;
    }

    public override int GetHashCode()
    {
        unchecked
        {
            int result = _hour;
            result = (result*397) ^ _minute;
            result = (result*397) ^ _second;
            return result;
        }
    }

}

public class OpeningHours
{
    public DayOfWeek DayOfWeek { get; set; }
    public Time OpeningTime { get; set; }
    public Time ClosingTime { get; set; }
    public OpeningHours(DayOfWeek dayOfWeek, Time openingTime, Time closingTime)
    {
        DayOfWeek = dayOfWeek;
        OpeningTime = openingTime;
        ClosingTime = closingTime;
    }
}