Entity Framework Sorting According to 2 columns at the same time

Question

I stucked at somewhere while developing our system. I have 2 different datetime columns DateModified and DateCreated. I want to sort my data according to those 2 columns at the same time. Like;

Id Name   DateCreated    DateModified
--------------------------------------------------------
1 Ali         2015-01-01       2015-02-02
2 Veli          2015-01-02       2015-02-03
3 Mehmed          2015-02-01       2015-02-05
4 Ahmed           2015-02-04        null

When I want to make a descending order by for those data, it should give me the result of

3 Mehmed
4 Ahmed
2 Veli
1 Ali

So... What is the way of doing that? Thanks

Answer 1

From what I understand you want the result to be sorted by both dates as a single property, not using ThenBy right?

Not a LINQ expert but I think this should work:

var Result = Items.OrderBy(x=> x.DateModified==null ? x.DateCreated : x.DateModified);

EDIT:

This goes on the assumption that the modify date is always after the creation date. In an general case it would look like this:

var Result = Items.OrderBy(x=> x.A >= x.B ? x.A : x.B);

Answer 2

use OrderBy and ThenBy

var Result = Items.OrderBy(x => x.DateModified).ThenBy(x => x.DateCreated);

Answer 3

If Ahmed is second, then you can use DateCreated instead of null: Items.OrderBy(a => a.DateModified != default(DateTime?) a.DateModified: a.DateCreated);