C# Is List contained in Another list?

I have this set:

List<short> delegatingUserRoles = await (from urols in _dbContext.UsersRoles
                                                        join u in _dbContext.Users on urols.UserId equals u.UserId
                                                        where (u.Username == delegation.UserDelegating)
                                                        select urols.RoleId).Distinct().ToListAsync();
            
            if (delegatingUserRoles.ConvertAll(i => (int)i).All(item => (delegation.UserSelectedRoles).Contains(item))){
                //true
            }

delegation.UserSelectedRoles is a list of int, subset of delegatingUserRoles

example delegatingUserRoles has values 1,2,3,4 while
delegation.UserSelectedRoles has values 1,2,3

Why it does not enter the if?

var l1 = new List<Int32> { 1 };
var l2 = new List<Int32> { 1,2,3 };

var r = l1.All(l => l2.Contains(l));

r = true

That Contains method tests whether a specific item is contained in a list. It doesn't test whether a list of items are all contained in a list. You could do this:

if (UserSelectedRoles.All(item => delegatingUserRoles.Contains(item))

Because the Contains() method checks if a single object is contained within the list, not if a list is contained within another list.

I think you need All() here.