I fleshed out your examples in a blog post here: http://hamishgraham.net/post/RE-IQueryable-vs-IEnumerable-in-LINQ-to-SQL-queries.aspx

Try this then…

@Venkat,

Try changing it to this:

var query = (from o in this.DBContext.mvc_getSelectGrids_ForProgramCode(paramProgramCode, start, limit, ref total)
select new
{
o.RgID,
o.GridLayoutLocation,
o.ObjectType,
o.Label,
o.AttribCodes
});

var list = query.ToList();
list = query.Skip(start).Take(limit).ToList();
int total = list.Count; // Invalid Operation Exception
return new AjaxStoreActionResult(list, total);

Thanks for quick response. It did not solve the problem.

This issue is in the same line as
http://social.msdn.microsoft.com/Forums/en-US/linqprojectgeneral/thread/f403e047-e38c-45ab-9155-dbf83c6cc2fa

Try changing it to this:

var query = (from o in this.DBContext.mvc_getSelectGrids_ForProgramCode(paramProgramCode, start, limit, ref total)
select new
{
o.RgID,
o.GridLayoutLocation,
o.ObjectType,
o.Label,
o.AttribCodes
});

query = query.Skip(start).Take(limit); // I moved this line up
int total = query.ToList().Count; // Invalid Operation Exception
return new AjaxStoreActionResult(query, total);

Controller Call:
——————
public AjaxStoreActionResult GetSelectRefGrids(int limit, int start, string dir, string sort, int paramProgramCode)

Case 1:
————–

var query = (from o in this.DBContext.mvc_getSelectGrids_ForProgramCode(paramProgramCode, start, limit, ref total)
select new
{
o.RgID,
o.GridLayoutLocation,
o.ObjectType,
o.Label,
o.AttribCodes
});

int total = query.ToList().Count; // <> Invalid Operation Exception
query = query.Skip(start).Take(limit);
return new AjaxStoreActionResult(query, total);

>> The Code fails returning Error as “Message = “The query results cannot be enumerated more than once.”
>>
>> So I changed Stored Procedure to Handle Paging and Return Total as OUT param

Case 2:
——————-

System.Nullable total = null
var query = (from o in this.DBContext.mvc_getSelectGrids_ForProgramCode(paramProgramCode, start, limit, ref total)
select new
{
o.RgID,
o.GridLayoutLocation,
o.ObjectType,
o.Label,
o.AttribCodes
});
return new AjaxStoreActionResult(query, total);

>> Any suggestions go by Case 1 and to handle the error “The query results cannot be enumerated more than once.” - Thanks Venkat

Does anyone know if a substitute exists for sql? I mean besides MS SQL and Oracle and all that jazz. Thanks.

I’m in a similar situation as you in that I was rewriting a legacy application. I have been very impressed with LINQ to SQL and I would highly recommend it. We are working with a legacy database (SQL Server 2005) that has some really unusual stuff in it, and LINQ to SQL has been able to handle it all.

IMO, if you want to get all of the benefits out of LINQ to SQL (or any ORM for that matter), I would try and get away from the stored procedures and allow LINQ to SQL to handle all the work. LINQ to SQL will optimize all of the queries for you, and if you do have a situation where you need to use stored procs, LINQ to SQL can wrap those nicely for you so that calling the stored proc is as easy as calling a method.

Good luck!

Jon