Last and LastOrDefault not supported

Question

I am trying to get the first and last values in a list. The query operator First() is supported but Last() and LastOrDefault() give an

Answer 1

either you switch your OrderBy to

.OrderByDescending(p => p.BillID)

(and use first) or you do something like

purchaseBills.ToArray().Last()

if this is not to expensive.

Answer 2

• Instead of putting it into an own list by calling ToList() or ToArray() i would prefer to use AsEnumerable().
• Additionally like the others you should try OrderByDescending()
• Instead of Count() i would use Any().

Answer 3

Yet another way get last element without orderbydescending and load all entities:

var lastBill = purchaseBills
    .Where(f => f.BillID == purchaseBills.Max(f2 => f2.BillID))
    .FirstOrDefault();

Answer 4

I try not to use LastOrDefault() because sometime it doesn't work or support. I'm sorting id by desc and then grab the first records.

.OrderByDescending(o=>o.id)
.FirstOrDefault(s => s.Name == Name)

Answer 5

It has something to do with the fact that the Last operator is trying to be sent to the SQL server which has no corresponding command. Once solution is to put a ToArray() or Tolist() at the end of your db call which makes that one line an explicit call to get the data (instead of lazing loading on each of the other lines).

Answer 6

Last is not supported by the back-end DB. You should try other techniques:

1. Run your query using OrderByDescending so your requested item comes first.

2. Code your LINQ query as usual, but enforce Linq2Sql to render it to a CLR collection and then you'll have free access to everything locally, including Last. Example:

   var bills = purchaseBills.ToList();
   var last = bills.Last();