CODEWITHSUNDEEP
c#linqdatetime
luisluix
luisluix

Reputation: 579

LINQ filter nullable datetime with matching params?

I need to filter my nullable datetime by day month and year.

I currently trying to do it by using string comparisons. I have this in where statement in linq:

DOB.ToString().StartsWith("2/25/19") || DOB == null

But its not working. I know its because the server doesnt store the date like that, but Im unsure as to how it is storing it, and how can I retrieve it and do the comparison.

I REALLY need this to happen on the database. I cant get everything and filter in the server.

I just want linq to filter dates by day, month, and year

Any help or pointers are appreciated.

Upvotes: 0

Views: 1289

Answers (3)

Floremin
Floremin

Reputation: 4089

You could try something like this (updated to include optional date components):

int? month = 2;
int? day = 25;
int? century = 19; // actual century minus one

// other LINQ here
.Where(x => x.DOB == null 
    || ((month == null || x.DOB.Month = month)
     && (day == null || x.DOB.Day = day)
     && (century == null || x.DOB.Year / 100 == century)));

Upvotes: 2

Triet Doan
Triet Doan

Reputation: 12085

If you want to filter by day, month, year, use the example code below:

    DateTime dateTime = DateTime.Now;
    Console.WriteLine(dateTime.Day);
    Console.WriteLine(dateTime.Month);
    Console.WriteLine(dateTime.Year);

You can get those value from DateTime object. Then, you can apply filter on it.

After reading the comment, I got your point.

For example, you enter a string like this:

string search = "2/25/2015";

Now, you want to extract the value of the string to perform filter, right? Simply do:

string[] values = search.Split('/');

Then, the values would be [2, 25, 2015]. First element is month, second is day, third is year, that depends on how you define the format.

Upvotes: 0

Luiso
Luiso

Reputation: 4113

try this:

context.Entities.Where(e => e.Date != null && e.Date.Day == 15)

you can use DateTime.Day, DateTime.Month, DateTime.Year and the logical operators && and || to filter as you see fit. You must however check for nullity first or you may end up with NullExceptions

Upvotes: 0

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