Comparing Dates, ignoring year - Linq/Entity Framework

Is there any easy way to compare dates, that ignores year, using Linq and the Entity Framework?

Say I have the following

var result = context.SomeEntity.Where(e => e.SomeDate > startDate);

This is assuming that SomeDate and startDate are .N开发者_如何转开发ET DateTime's.

What I would like to do is compare these dates without comparing year. SomeDate can be any year. Is there any easy way to do this? The only way I could think of would be to use the following:

var result = context.SomeEntity(e => 
    e.SomeDate.Month > startDate.Month ||
    (e.SomeDate.Month == startDate.Month && e.SomeDate.Day >= startDate));

This method quickly gets more complicated if I am looking to have an endDate as well, as I will have to do things like take account for when the start date is at the end of the year and the end date is at the beginning.

Is there any easy way to go about this?

Update:

I ended up just going about it the way I had initially thought in the post... a heck of a lot of code for something conceptually simple. Basically just had to find if a date fell within a range, ignoring year, and looping the calendar if startDate > endDate If anyone knows an easier way, please post as I am still interested.

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If you really need to compare only dates (not times) then DateTime.DayOfYear property might help. But you should be careful regarding leap years in this case. Other of this I cannot imagine anything more simple than your approach with comparing months and days.

If all you care about is that this method will become more complicated after introducing second comparison then simple method extraction should help.

Another approach might be creating an extension method which will return a number applicable for your comparison. For example let's call this method GetYearIgnoringOrdinal():

public static int GetYearIgnoringOrdinal(this DateTime date)
{
    return date.Month*100 + date.Day;
}

And then use it like this:

var result = context.SomeEntity.Where(e => e.SomeDate.GetYearIgnoringOrdinal() > startDate.GetYearIgnoringOrdinal());

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Slightly simpler looking way

var result = context.SomeEntity(e => 
    e.SomeDate.Month * 100 + e.SomeDate.Day > startDate.Month * 100 + startDate.Day
);

You could also create a user defined function (assuming SQL server is used) and that function can be used in the query.