你可以简单地使用Split

 new TimeSpan(new DateTime(1970, 1, 1).Ticks).TotalSeconds.ToString().Split('.')[0]

我知道答案很晚了，但是摆脱毫秒的最好方法是

var currentDateTime = DateTime.Now.ToString("s");

尝试打印变量的值，它将显示日期时间，没有毫秒。

与其放弃毫秒然后比较，为什么不比较差异呢?

DateTime x; DateTime y;
bool areEqual = (x-y).TotalSeconds == 0;

or

TimeSpan precision = TimeSpan.FromSeconds(1);
bool areEqual = (x-y).Duration() < precision;

在我的情况下，我的目标是从datetimePicker工具保存TimeSpan，而不节省秒和毫秒，这里是解决方案。

首先转换datetimePicker。值转换为你想要的格式，我的格式是“HH:mm”，然后将其转换回TimeSpan格式。

var datetime = datetimepicker1.Value.ToString("HH:mm");
TimeSpan timeSpan = Convert.ToDateTime(datetime).TimeOfDay;

2上述解决方案的扩展方法

    public static bool LiesAfterIgnoringMilliseconds(this DateTime theDate, DateTime compareDate, DateTimeKind kind)
    {
        DateTime thisDate = new DateTime(theDate.Year, theDate.Month, theDate.Day, theDate.Hour, theDate.Minute, theDate.Second, kind);
        compareDate = new DateTime(compareDate.Year, compareDate.Month, compareDate.Day, compareDate.Hour, compareDate.Minute, compareDate.Second, kind);

        return thisDate > compareDate;
    }


    public static bool LiesAfterOrEqualsIgnoringMilliseconds(this DateTime theDate, DateTime compareDate, DateTimeKind kind)
    {
        DateTime thisDate = new DateTime(theDate.Year, theDate.Month, theDate.Day, theDate.Hour, theDate.Minute, theDate.Second, kind);
        compareDate = new DateTime(compareDate.Year, compareDate.Month, compareDate.Day, compareDate.Hour, compareDate.Minute, compareDate.Second, kind);

        return thisDate >= compareDate;
    }

用法:

bool liesAfter = myObject.DateProperty.LiesAfterOrEqualsIgnoringMilliseconds(startDateTime, DateTimeKind.Utc);

var date = DateTime.Now;

date = new DateTime(date.Year, date.Month, date.Day, date.Hour, date.Minute, date.Second, date.Kind);