Converting DateTime when using LINQ and WebAPI?

Question

I am having problem with converting the DateTime I am collecting from the database to localtime with LINQ. A LINQ query won't let me use ToLocalTime() and I can't seem to get any fix outside the query to work with the anonymous type of list.

Here is the LINQ query from the controller :

                    // GET: api/Scan
    public object Getv_Update_ComplianceStatusAll()
    {
        var dato = DateTime.Now.AddYears(-1);


        var scan = (from n in db.C_RES_COLL_NO9000AC
                    join s in db.v_Update_ComplianceStatusAll on n.MachineID equals s.ResourceID
                    join u in db.v_UpdateInfo on s.CI_ID equals u.CI_ID
                    join c in db.v_CICategoryInfo on u.CI_ID equals c.CI_ID
                    where (n.MachineID == s.ResourceID) && (u.DateRevised > dato) 
                    group s by new { n.Name } into grp
                    select new
                    {
                        Name = grp.Key.Name,
                        StatusScan = grp.Max(t=> t.LastStatusCheckTime)


                    });


        return scan;
    }

This is my attemt at a fix outside the query :

            var newScan = scan.ToList();

        foreach (var s in newScan)
        {

            s.StatusScan = s.StatusScan.ToLocalTime();
        }

        return newScan;

The converstion works, but it returns "Error 306 Property or indexer 'AnonymousType#1.StatusScan' cannot be assigned to -- it is read only"

So, how do I convert the UTC to local time in the controller (before I return anything to the website)?

have you tried to use a strongly typed variable instead? I.e.: Creating a ViewModel? — Marco
– Marco, Commented May 8, 2015 at 5:22
Do you need local time of the server or local time of the client? — genichm
– genichm, Commented May 8, 2015 at 5:29

Eric · Accepted Answer · 2015-05-08 05:40:23Z

1

Yes, Anonymous Type is handy, but it is a bad idea to return it from a method -- Outsider do not know what actually the object is. It is recommended to create a strong type to store the result and return IEnumerable<ScanItem>. Then you are able to modify the result.

public class ScanItem
{
    public string Name { get; set; }
    public datetime StatusScan { get; set; }
}

If you must use Anonymous Type, You can build a new list like this

scan.ToList().Select(i => new {Name = i.Name, StatusScan = i.StatusScan.ToLocalTime()});

edited May 8, 2015 at 5:40

answered May 8, 2015 at 5:32

Eric

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Yu Yenkan · Accepted Answer · 2015-05-08 05:27:31Z

0

    var newScan = scan.ToList();

    foreach (var s in newScan)
    {
        s.StatusScan = s.StatusScan.ToLocalTime();
    }

    return newScan;

your newScan is a List, you cannot directly assign

s.StatusScan = s.StatusScan.ToLocalTime();

answered May 8, 2015 at 5:27

Yu Yenkan

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