Property 'Int32 Year' is not defined for type 'System.Nullable`1[System.DateTime]' When comparing year in two dates

Question

Property 'Int32 Year' is not defined for type 'System.Nullable`1[System.DateTime]' When comparing year in two dates

c# entity-framework entity-framework-core

Question

I've got strange exception when comparing year in datetime.

sample code:

_dbContext.Details.Where(x => x.Person.Birth.Year == date.Year);

Where both Birth and date are not nullable DateTime.

Exception message:

Message: System.ArgumentException : Property 'Int32 Year' is not defined for type 'System.Nullable`1[System.DateTime]'

I tried to run the code from unit tests with database set up in memory.

Pawel

Popular Answer

So, it seems you have "DateTime?" instead of "DateTime". That way, you have to check something like that:

_dbContext.Details.Where(x => date.HasValue && (x.Person.Birth.Year == date.Value.Year));

Yury Schkatula

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Pawel · Accepted Answer · 7/24/2017 3:41:07 PM

My model definition was wrong and I didn't specify foreign key correctly.

It looked similar to that (after renaming from PerId to PersonId the problem was gone):

public class Person
{
    public int Id {get; set;}
    public DateTime Birth {get; set;}
}

public class Details 
{
    public int Id {get; set;}
    public int PerId {get; set;}
    public Person Person {get; set;}
}

Property 'Int32 Year' is not defined for type 'System.Nullable`1[System.DateTime]' When comparing year in two dates

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