Ordering a list of objects by another object's property in C#

Question

We have a system that is based around Events that Users are invited to [UserInvite].

Currently, I have a page that lists all the Users invited to an Event; they can be sorted by various properties, such as Surname [ascending and descending]. All fine and dandy, but now I'm required to additionally sort by a UserInvite property: DateEdited [again asc/desc]. I've been using an extension method that takes in a string of the property name to sort by, but this won't work for another class's property.

Notes:

1. UserInvite has a method to get by Event and User which always returns a single UserInvite [or null if no invite was found].
2. The current EventID is held in the Master page so can be reached on the page that lists the Users

What is the best way to do this?

Answer 1

Is there a route from the Event to the UserInvite? If so, simply walk the relation. Actually, the simplest approach is to re-expose this date on the Event - i.e.

public DateTime InviteDate {get {return Invite.Date;}} // or similar

and order by InviteDate - but you can also use a string like "Invite.Date" and split it by dots - for example, here's something similar for IQueryable<T> - although it doesn't handle null at the moment.