Version 10

[a-gubskiy]

No description provided.

[adschmu]

Note that there isn't really much point to creating a PagedList without a superset.

Personally, I would make the superset argument here non-nullable, throw an exception if it is, and drop the nullable handling after that point.

If somebody really wants a PagedList that is empty, he could still supply an empty list to the constructor. This would look like this:

public PagedList(IQueryable<T> superset, Expression<Func<T, TKey>> keySelector, int pageNumber, int pageSize)
        : base(pageNumber, pageSize, superset.Count())
    {
        if (superset == null)
            throw new ArgumentNullException(nameof(superset));

        // add items to internal list
        if (TotalItemCount > 0)
        {
            InitSubset(superset, keySelector.Compile(), pageNumber, pageSize);
        }
    }

I would do the same to equivalent cases, i.e. never allow null for the superset anywhere.
This also means that you do not have to change InitSubset at all.

[a-gubskiy]

Agree

[adschmu]

I'll prepare two commits for nullable changes as suggested above and for the direct Subset assignment.

[adschmu]

I've taken the liberty to rebase this onto my #278 for a cleaner history in #279