CODEWITHSUNDEEP
c#asp.net-mvclinq
Trent Stewart
Trent Stewart

Reputation: 881

Creating an array then selecting based on it

I need a linq call to return a list of floor id's in an array format so that I am able to use it to do a Contains call to return all the related data.

I can't get linq to return an array of floors.

var myFloors = 
(from f in db.Floor
where f.BuildingId == txBuildingId
select new { f.FloorId }).ToArray();

Then, I am having trouble selecting based on that Array.

var model =
(from r in db.Room
where myFloors.Contains(r.FloorId) 
select new
{
    label = r.Name,
    value = r.RoomId
});

I could do this easily in SQL with a string and by using the IN clause. I am fairly new to LINQ and am having alot of trouble with this. Any help would be much appreciated.

Upvotes: 1

Views: 89

Answers (2)

cuongle
cuongle

Reputation: 75326

No need to have anonymous type in here, you can select floorId directly:

var myFloors = 
(from f in db.Floor
where f.BuildingId == txBuildingId
select f.FloorId);

For more readable, I prefer using lambda style:

var myFloors = db.Floor.Where(f => f.BuildingId == txBuildingId)
                       .Select(f => f.FloorId);

So:

var model = db.Room.Where(r => myFloors.Contains(r.FloorId))
                   .Select(r => new {
                        label = r.Name,
                        value = r.RoomId    
                    });

Upvotes: 3

zs2020
zs2020

Reputation: 54543

If you have Floor reference defined in Room, you can merge the 2 Linq queries to one, which is more efficient in terms of performance.

db.Room.Where(x=>x.Floor.BuildingId == txBuildingId).Select(r => new {
    label = r.Name,
    value = r.RoomId
})

Upvotes: 1

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