Cannot implicitly convert type 'System.Linq.IQueryable' to 'System.Collections.Generic.IList'

To convert IQuerable or IEnumerable to a list, you can do one of the following:

IQueryable<object> q = ...;
List<object> l = q.ToList();

or:

IQueryable<object> q = ...;
List<object> l = new List<object>(q);

You can replace IList<DzieckoAndOpiekun> resultV with var resultV.

If using a where clause be sure to include .First() if you do not want a IQueryable object.