Order by Descending with multiple comparisons

Question

I want to order the result with multiple comparisons like (by paid users, updated date, created date).

var order = _vrepository.Details()
                          .Where(od => od.Order.Id != null
                                       && od.PlanName.ToLower().Contains("DP".ToLower())
                                       && od.Order.Status == true)
                          .OrderByDescending(od => od.ValidityTill)
                          .Select(ord => ord.Order.Id.Value);

The above one I am getting the paid users.

var updatedList = _repository.GetUsers()
                             .Where(c => c.UpdatedDate != null
                                         && fresh <= c.UpdatedDate)
                             .Select(c => c.Id);

This second query I am getting updated users.

var UsersListByCreatedDate = _repository.GetUsers()
                                        .Where(c => fresh <= c.CreatedDate)
                                        .Select(c => c.Id);

The third one is for get the users by created date. Then I am selecting the Id (an Integer)

lstId = order.ToList();
lstUpdatedUsersId = updatedList ToList();
lstCreatedDatewiseUsers = UsersListByCreatedDate.ToList();

To show the ordered list I did the following code:

Func<IQueryable<User>, IOrderedQueryable<User>> orderingFunc = query =>
{
    if (order.Count() > 0)
        return query.OrderByDescending(rslt => lstId .Contains(rslt.Id))
                    .ThenByDescending(rslt => lstUpdatedUsersId .Contains(rslt.Id))
                    .ThenByDescending(rslt => lstCreatedDatewiseUsers.Contains(rslt.Id));
    else
        return query.OrderByDescending(rslt => lstUpdatedUsersId .Contains(rslt.Id))
                    .ThenByDescending(rslt => rslt.UpdatedDate);
};

But I am getting result as One Paid user, some Created user and the date is before 3 years like wise. I want to get the exact order is as follows

Ordered User
Updated User
Created User

Please help me to solve this issue. Hope I will get correct result.

possible duplicate of [Multiple "order by" in LINQ](http://stackoverflow.com/questions/298725/multiple-order-by-in-linq) — Orace, Apr 08 '15 at 13:45
No. I could not. nobody is given me a correct answer. i tried. but it is not showing the exact result — PoliDev, Apr 11 '15 at 11:25
Why the wrong results? In my answer which is the wrong behavior? — faby, Apr 15 '15 at 06:03

score 0 · Answer 1 · answered Apr 08 '15 at 13:33

I have tried this snipepd of code according to your

public class Program
{
    public static void Main()
    {
        var l1= new List<int>{1,2,3};
        var l2= new List<int>{4,5,6};
        var l3= new List<int>{7,8,9};
        var testList = new List<Test>{new Test{Id=9,Name="test1"},new Test{Id=11,Name="test1"},new Test{Id=5,Name="test1"},new Test{Id=7,Name="test1"},new Test{Id=2,Name="test1"}};
        var orderedList= testList.OrderByDescending(e=> l1.Contains(e.Id)).ThenByDescending(e=> l2.Contains(e.Id)).ThenByDescending(e=> l3.Contains(e.Id));
        Console.WriteLine(string.Join("\t", orderedList.Select(e=> e.Id).Cast<int>().ToArray()));
// it prompts 2    5    9    7    11
    }
}

public class Test{
    public int Id{get; set;}
    public string Name{get; set;}
}

and it works as you expected. Maybe I haven't understood what you are trying to achieve. Maybe the function that you are using to sort items is in the wrong branch of the if statment, check for if (order.Count() > 0)

Order by Descending with multiple comparisons

1 Answers1