Simple way to compare Dates in DateTime attribute using Entity Framework 4 and Linq queries

Question

I'm trying to run the following bit of code, but the comparison fails by not handing my the entities I expect it to.

It's comparing 06/09/2011 0:00:00 to 06/09/2011 12:25:00, the latter being my databases record value. So that's why the comparison is failing and I'm not getting the records I need.

I'm just trying to compare if the dates match up, I'm don't care about the time.

DateTime today = DateTime.Now.Date;
var newAuctionsResults = repo.FindAllAuctions()
                        .Where(a => a.IsActive == true || a.StartTime.Value == today)
                        .ToList();

How can I compare only the dates?

If use the .Date property in the .StartTime.Value part, I get an exception:

The specified type member 'Date' is not supported in LINQ to Entities. Only initializers, entity members, and entity navigation properties are supported.

Maybe this question will help? LINQ | How do I perform Date Comparison in a Linq Query? http://stackoverflow.com/questions/1088212/linq-how-do-i-perform-date-comparison-in-a-linq-query — Kyle, Sep 06 '11 at 13:31

score 16 · Accepted Answer · answered Sep 06 '11 at 13:28

You can use the individual members:

var newAuctionsResults = repo.FindAllAuctions()
                        .Where(a => a.IsActive == true 
                                    || (a.StartTime.Value.Year == todayYear
                                        && a.StartTime.Value.Month == todayMonth
                                        && a.StartTime.Value.Day == todayDay))
                        .ToList();

...or use any of the other methods/properties supported in L2E.

It is being used for equal operator. What if I need to check greater than and less than operator. — Usman Khalid, Apr 14 '15 at 12:13

score 11 · Answer 2 · answered Dec 05 '13 at 10:18

11

You can also use EntityFunctions.TruncateTime() under the namespace System.Data.Objects

Ex.

db.Orders.Where(i => EntityFunctions.TruncateTime(i.OrderFinishDate) == EntityFunctions.TruncateTime(dtBillDate) && i.Status == "B")

Works like charm.

answered Dec 05 '13 at 10:18

صفي

1,068
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How do you write UnitTests then? – Hossein Shahdoost Feb 09 '16 at 11:12
EntityFunctions are now obsolete, use DbFunctions instead! – Daniel Vygolov Jan 26 '17 at 21:39

score -1 · Answer 3 · answered Sep 06 '11 at 13:27

try

DateTime todayStart = DateTime.Now.Date;
DateTime todayEnd = DateTime.Now;
var newAuctionsResults = repo.FindAllAuctions()
                        .Where(a => a.IsActive == true || (a.StartTime.Value >= todayStart && a.StartTime.Value <= todayEnd))
                        .ToList();

score -2 · Answer 4 · answered Sep 06 '11 at 13:27

-2

You could convert using

DateTime.ToShortDateString()

http://msdn.microsoft.com/en-us/library/system.datetime.toshortdatestring.aspx

This would neglect the Time.

Then compare the two Strings.

if(string1 == string2)
{
 //Do Something
}

answered Sep 06 '11 at 13:27

Mac

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[Not supported in L2E](http://msdn.microsoft.com/en-us/library/bb738681.aspx), I'm afraid. – Craig Stuntz Sep 06 '11 at 13:29

Simple way to compare Dates in DateTime attribute using Entity Framework 4 and Linq queries

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