How to use orderby with 2 fields in linq?

Question

hi

Say I have these values in a database table

id = 1
StartDate = 1/3/2010
EndDate =  1/3/2010

id = 2
StartDate = 1/3/2010
EndDate = 1/9/2010

Now I have so far this orderby for my linq

var hold = MyList.OrderBy(x => x.StartDate).ToList();

I want to order it however also using the end date.

Like so the order I would want this in as

id 2
id 1

So endDates that are greater go first. I am not sure if I need to change this to use some compare function or something.

Thanks

Answer 1

MyList.OrderBy(x => x.StartDate).ThenByDescending(x => x.EndDate);

Answer 2

Use ThenByDescending:

var hold = MyList.OrderBy(x => x.StartDate)
                 .ThenByDescending(x => x.EndDate)
                 .ToList();

You can also use query syntax and say:

var hold = (from x in MyList
           orderby x.StartDate, x.EndDate descending
           select x).ToList();

ThenByDescending is an extension method on IOrderedEnumerable which is what is returned by OrderBy. See also the related method ThenBy.

Answer 3

There's a good explanation of another approach to muliple orderbys here.