如何在 c# 中创建扩展以返回可以在 linq 中转换为实体的新日期时间条目？

Question

So I have this property in a LinQ to entity query and I need to add days to it

isWithinNinetyDays = (a.ParcelData == null ? false :
    (a.ParcelData.Parcel_LetterTracking == null ? false : 
        (a.ParcelData.Parcel_LetterTracking.LMailDate == null ? false : 
            (System.Data.Entity.DbFunctions.AddDays(a.DateTimeEntry, 90) >= a.ParcelData.Parcel_LetterTracking.LMailDate.Value)))),

The issue is I don't want to use "System.Data.Entity.DbFunctions.AddDays(a.DateTimeEntry, 90)" because I'm going to have to do this a lot and it's just so ugly to write that everytime... is it possible to make an extension where I can just call

a.DateTimeEntry.MyExtension(90)
that will add 90 days and be able to convert it to a entity convertable to sql object? 

Answer 1

Use a using statement.

using System.Data.Entity;
DBFunctions.AddDays(a.DateTimeEntry, 90) ...