Check dates fall into range using Linq

Question

I'm currently working on what requires checking for two dates. My current methods do not return the expected result. For example, let's say I have the following reservations:

• 04/13/2015 to 04/18/2015
• 04/15/2015 to 04/20/2015
• 04/10/2015 to 04/16/2015

and I want to see all reservations that are between 04/15/2015 to 04/16/2015. Visually, it might look like this:

              15    16
      X________|_____|______X
               |X____|_____________X
X______________|____X|
               |     | 

To get all reservations that relate to these dates, I use:

public List<ReservationClientModel> GetReservationsByDateRange(int id, DateTime checkin, DateTime checkout)
    {
        var reservation = _repository.FindAllBy(x => 
            (x.StartDate >= checkin && x.EndDate <= checkout) ||
            (x.StartDate >= checkin && x.StartDate <= checkout) ||
            (x.EndDate >= checkin && x.EndDate <= checkout)),
            y => y.RoomTypeNav)
            .ToList();

        return Mapper.Map<List<ReservationClientModel>>(reservation);
    }

Uses:

public IEnumerable<TEntity> FindAllBy(Expression<Func<TEntity, bool>> predicate, params Expression<Func<TEntity, object>>[] includes)
    {
        var set = _dbSet.AsQueryable();
        set = includes.Aggregate(set, (current, include) => current.Include(include));
        return set.Where(predicate);
    }

, , , >= <= , , . SQL BETWEEN, , Linq #? EF, , .

.

Answer 1

, :

(StartDate1 <= EndDate2) and (EndDate1 >= StartDate2)

, :

var reservation = _repository
    .FindAllBy(x => x.StartDate <= checkout && x.EndDate >= checkin,  
               y => y.RoomTypeNav)
    .ToList();