To apply mulitple criteria in lambda expression in c#

Question

I have two main tables Listings and Place . In listing table there is a field PlaceId which referes to a Place entity/row/object . I want to query on both tables so that i get both of them like this .

 var query = context.Listings
       .Include("Place")
       .Where(l => l.Place.TypeId == Type.Ro)
       .OrderBy(l => l.Id).ToList();

after this now i want to put some filter on this query , here is the condition .

i got only a string like this var filter = "1,2,4"; . Now i want to filter on listing to gett all these listing where bedroom is equal to 1 OR 2 OR 4 .

What i have done

 string minBeds = "1,2,4";

 foreach (var item in minBeds.Split(','))
 {
      int minBed = int.Parse(item);
      query = query.Where(l=>l.Place.Bedroom == minBed).ToList();
 }

But doing this is giving me Zero result.

Answer 1

The problem with the way you're filtering it. After the first pass, you're filtering out everything except where Bedroom == 1 , on the second pass you're filtering out everything except where Bedroom == 2 , but since the only items in the list have Bedroom == 1 , you won't have anything in the result set.

The solution is to use the conventional C# || operator:

query = query.Where(l => l.Place.Bedroom == "1" || 
                         l.Place.Bedroom == "2" || 
                         l.Place.Bedroom == "4");

Or if you want to be more flexible, use the Contains method:

string[] minBeds = "1,2,4".Split(',');
query = query.Where(l => minBeds.Contains(l.Place.Bedroom));

Note if Bedroom is an integer, you'll need to convert the input to an appropriate type first:

var minBeds = "1,2,4".Split(',').Select(int.Parse);
query = query.Where(l => minBeds.Contains(l.Place.Bedroom));

Also note, I've eliminated the ToList here. Unless you need to access items by index and add / remove items from the result collection, it's most likely just a waste of resources. You can usually rely on Linq's native laziness to delay processing to query until you really need the result.