Linq - 通过标签缩小事件的列表对象

Question

I'm a little bit stumped with this Linq statement. My basic database structure is:

• Event (ID, Name, VenueID)
• Venue (ID, Name)
• EventTag (EventID, TagID)
• VenueTag (VenueID, TagID)
• Tag (TagID, Name)

I have a list of events, and I want to narrow it down by events that either contain the specified tag, or the venue they are held at contain the tag.

I have tried this, and I think I may not be too far off, but I'm still struggling to get it to work:

eventsList = eventsList
                .SelectMany(x => x.EventTag)
                .Where(et => et.TagID == tagID)
                .Select(et => t.Event)
                .Union(eventsList.SelectMany(x=>x.Venue.VenueTag)
                .Where(vt =>vt.TagID == tagID)
                .Select(vt=>vt.Venue.Event)
                .Distinct()
                .ToList();

I'd be very grateful for any help!

Andy

Answer 1

You can use Any for this:

eventsList.Where(
              x => x.EventTag.Any(et => et.TagID == tagID)
                   || x.Venue.Any(v => v.Any(vt => vt.TagID == tagID)))
          .ToList();