Remove entries from list of a generic list

Question

I have a model class like this

    public class InterestList
{
    public string id { get; set; }
    public string name { get; set; }
    public string description { get; set; }
    public List<Interest> interests { get; set; }
}
public class Interest
{
    public string id { get; set; }
    public int sortOrder { get; set; }
    public string name { get; set; }
    public string categoryName { get; set; }
    public string categoryId { get; set; }
}

And an object private List<InterestList> _interestlist; which holds my data.

as you can see _interestlist contains a list of Interest named interests now i want to remove a single entry of it. How can I achieve this with Linq?

I have tried like

   _interestlist.RemoveAll(x => x.id == "1234");

but it removes interests only not Interest. Can any one point out the right way?

Answer 1

This code:

_interestlist.ForEach(i => i.interests.RemoveAll(x => x.id == "1234"));

will delete all objects in the interests lists contained in any of your InterestList objects in _interestlist with id = "1234".

Answer 2

Technically you have a lists of lists, almost as if you had List<List<Interest>>. To solve this problem you will need to foreach over your collection and perform the Remove operation on the inner list.

foreach(InterestList interestList in _interestlist)
{
    interestList.interests.RemoveAll(x => x.id == "1234");
}

You also could use the ForEach method built in to List<T>

_interestlist.Foreach(i => i.interests.RemoveAll(x => x.id == "1234"));