Problem with Converting Datetime to String in Linq

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Hi,

I'm trying to convert Nullable Datetime to string in my Linq Query. And I get this error

LINQ to Entities does not recognize the method 'System.Nullable`1[System.Int32] DatePart(System.String, System.Nullable`1[System.DateTime])' method, and this method cannot be translated into a store expression.

Please help me

[EDIT - OP's code from comment]

C#

from p in TreatmentDetails
    select new
    {
        p.Id,
        p.TotalQty,
        p.Dose,
        p.IsStop,
        p.Note,
        p.TandFId,
        PrescriptionDate = SqlFunctions.DateName("day", p.PrescriptionDate).Trim() + "/" +
        SqlFunctions.StringConvert((double)p.PrescriptionDate.Value.Month).TrimStart() + "/" +
        SqlFunctions.DateName("year", p.PrescriptionDate)
                                    }).ToList();

Posted 17-Jan-14 21:45pm

arahaman.ashik

Updated 18-Jan-14 3:55am

Ron Beyer

v3

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Comments

Karthik_Mahalingam 18-Jan-14 3:48am

post your code..

Tejas Vaishnav 18-Jan-14 6:03am

can you share your linq code...

arahaman.ashik 18-Jan-14 9:47am

from p in TreatmentDetails
select new
{
p.Id,
p.TotalQty,
p.Dose,
p.IsStop,
p.Note,
p.TandFId,
PrescriptionDate = SqlFunctions.DateName("day", p.PrescriptionDate).Trim() + "/" +
SqlFunctions.StringConvert((double)p.PrescriptionDate.Value.Month).TrimStart() + "/" +
SqlFunctions.DateName("year", p.PrescriptionDate)
}).ToList();

Ganesh KP 18-Jun-14 2:14am

Thanks for your answer. It helps me.

2 solutions

Solution 2

LINQ Does not allow you to do any type of converting
you can do your converting out of linq code

Posted 18-Jan-14 21:52pm

muntaser zalloum

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Raul Iloc · Accepted Answer · 2014-01-18T22:33:00

Solution 3

Your error seems to be generated from your next code section:

SqlFunctions.StringConvert((double)p.PrescriptionDate.Value.Month).TrimStart();

and especially the usage of:

p.PrescriptionDate.Value.Month

So you should modify this code section by using:

DateName("month", p.PrescriptionDate).Trim()

Posted 18-Jan-14 22:33pm

Raul Iloc

Updated 18-Jan-14 22:35pm

v4

Comments

arahaman.ashik 19-Jan-14 10:39am

Thanks for your answers, but I tried this,
DateName("month", p.PrescriptionDate).Trim()

and get the same error...

Raul Iloc 20-Jan-14 4:23am

In this case you should modify your code to manage the case when your DateTime is null.
You should do change in the next manner:
select new{ ...
PrescriptionDate == null ? " " : "[your old code]"
}).ToList();

so in the case of DateTime null I put string space but you could put the string that you want.