Trying to Filter a collection using LINQ where the collection has a collection which also has a collection with a property that is nullable

Question

Ok, this has been a pretty interesting problem for me to solve, so I will try and do my best to ask this in a way in which you can understand.

So, I have a collection of objects which contains a collection of objects which contains a collection of objects which has a property that sometimes can be null.

It looks something like this pseudocode:

Class ObjectA 
{
    public IEnumerable<ObjectB>
}

Class ObjectB 
{
    public IEnumerable<ObjectC>
}

Class ObjectC  
{
    property? a;
}

Ok, now I basically need to filter out all of the ObjectC where the property = someValue or the property is null.

I tried this: (remember, this is just an example, not real code)

IEnumerable<ClassA> collection;
List<string> filters; // This contains a list of filters
collection = collection.Where(a => a.collectionB.All(b =>
    b.collectionC.Where(c => !filter
        .Contains(c.Property))?
        .Count() == 0))
        .ToList();

So, the problem is that if I match a filter to the c.Property nothing happens. It should remove that one from the collection but it isn't. I also need to not filter out any of the ones where the c.Property == null or the collectionC == null.

EDIT: what I am really trying to accomplish is if some c.Property = 'x' and some c.Property = 'y' and some c.Property = null, I want to remove from my collection anything where c.Property = 'x' but leave the rest.

Answer 1

collection.Where(a=>a.collectionB.Any(b=> b.collectionC == null ||
   b.collectionC.Any(c=>c.Property == null || filters.Contains(c.Property))))