OrderBy descending in Lambda expression?
Question
I know in normal Linq grammar, orderby xxx descending
is very easy, but how do I do this in Lambda expression?
Accepted Answer
As Brannon says, it's OrderByDescending
and ThenByDescending
:
var query = from person in people
orderby person.Name descending, person.Age descending
select person.Name;
is equivalent to:
var query = people.OrderByDescending(person => person.Name)
.ThenByDescending(person => person.Age)
.Select(person => person.Name);
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Use System.Linq.Enumerable.OrderByDescending()
?
For example:
var items = someEnumerable.OrderByDescending();
Try this another way:
var qry = Employees
.OrderByDescending (s => s.EmpFName)
.ThenBy (s => s.Address)
.Select (s => s.EmpCode);
This only works in situations where you have a numeric field, but you can put a minus sign in front of the field name like so:
reportingNameGroups = reportingNameGroups.OrderBy(x=> - x.GroupNodeId);
However this works a little bit different than OrderByDescending
when you have are running it on an int?
or double?
or decimal?
fields.
What will happen is on OrderByDescending
the nulls will be at the end, vs with this method the nulls will be at the beginning. Which is useful if you want to shuffle nulls around without splitting data into pieces and splicing it later.
LastOrDefault()
is usually not working but with the Tolist()
it will work. There is no need to use OrderByDescending
use Tolist()
like this.
GroupBy(p => p.Nws_ID).ToList().LastOrDefault();