DateTime comparison without time part?

Question

I wrote this code. But I want to ignore time, I want to compare only day.

from s in sayac_okumalari
where s.okuma_tarihi == startDate && s.sayac_id == sayac_id
group s by new { date = new DateTime(((DateTime)s.okuma_tarihi).Year, ((DateTime)s.okuma_tarihi).Month, ((DateTime)s.okuma_tarihi).Day, ((DateTime)s.okuma_tarihi).Hour, 1, 1) } into g
select new
{
     okuma_tarihi = g.Key.date,
     T1 = g.Sum(x => x.toplam_kullanim_T1),
     T2 = g.Sum(x => x.toplam_kullanim_T2),
     T3 = g.Sum(x => x.toplam_kullanim_T3)
};

for example:

25.02.1987 == 25.02.1987

Solution 1

use s.okuma_tarihi.Value.Date == startDate.Date. This should allow you to compare only the Date component.

Update From the discussion in comments looks like the user is using NullableType. Hence updated the solution for NullableType.

Solution 2

Use Date property of DateTime. For ex,

var date= DateTime.Now.Date;

Solution 3

Because you could convert s.okuma_tarihi to DateTime, I think you could do:

var sonuc = from s in sayac_okumalari
        where (DateTime)s.okuma_tarihi.Date == startDate.Date && s.sayac_id == sayac_id
        group s by new { date = new DateTime(((DateTime)s.okuma_tarihi).Year, ((DateTime)s.okuma_tarihi).Month, ((DateTime)s.okuma_tarihi).Day, ((DateTime)s.okuma_tarihi).Hour, 1, 1) } into g
        select new
        {
             okuma_tarihi = g.Key.date,
             T1 = g.Sum(x => x.toplam_kullanim_T1),
             T2 = g.Sum(x => x.toplam_kullanim_T2),
             T3 = g.Sum(x => x.toplam_kullanim_T3)
        };

Hope it helps.

Comments

[Veverke]

Possible duplicate of How to compare only Date without Time in DateTime types in C#?

[AliRıza Adıyahşi]

's.okuma_tarihi' does not contain a definition for 'Date'

[Ramesh]

Looks like from your code snippet, you need to typecast s.okuma_tarihi to DateTime

[AliRıza Adıyahşi]

s.okuma_tarihi.Value.Date == startDate.Date is working.If edit your solution I will mark it. Thanks.

[AliRıza Adıyahşi]

((DateTime)s.okuma_tarihi).Date use only calling, assigment.

[Ramesh]

Updated. But, looks like you are using Nullable type. You may need to ensure that Nullable type has value before performing action.

[AliRıza Adıyahşi]

This is usefull knowledge for me. Thanks a lot.