asp.net - Entity Framework 和 Linq - 比较 DateTime

Question

我有这个代码

public List<CalendarData> GetCalendarData(DateTime day)
    {
        List<CalendarData> list = new List<CalendarData>();
        using (dataContext = new VTCEntities())
        {

            DateTime test = new DateTime(2010, 10, 20, 17, 45, 0);

            var data = from z in dataContext.ReservationsSet
                       where z.start_time.Value == test
                       select z;

            foreach (var r in data)

我想做的就是拥有这个

var data = from z in dataContext.ReservationsSet
                   where z.start_time.Value == day
                   select z;

我遇到的问题是 z.start_time 也有时间部分。 DateTime 日没有记录时间部分。有没有办法比较日期部分而不会出现此错误

The specified type member 'Date' is not supported in LINQ to Entities. Only initializers, entity members, and entity navigation properties are supported. 

当我这样做时

var data = from z in dataContext.ReservationsSet
           where z.start_time.Value.Date == test
           select z;

Answer 1

一种选择是计算两个值，如下所示:

DateTime day = ...;
DateTime nextDay = day.AddDays(1);

var data = from z in dataContext.ReservationsSet
                   where z.start_time.Value >= day &&
                         z.start_time.Value < nextDay
                   select z;