NHibernate QueryOver - Doing Fetches and OrderBy -> What Syntax to use?

All,

I have a query as such:

_AddOrderBy(sortOptions, query)
                .Fetch(x => x.ImageType).Eager
                .Fetch(x => x.User).Eager
                .Fetch(x => x.Partner).Eager
                .Inner.JoinAlias(x => x.Partner, () => p).Fetch(x => x.Company).Eager

                .Skip(startIndex)
                .Take(pageSize)
                .List<ImageRequest>();

In the above QueryOver I call _AddOrderBy() method which adds an order by clause. The challenge I face is how do I create an "order by" that references a property (ordering by "CompanyName") that lies within the following association path without conflicting with my Fetch()/Inner joins:

ImageRequest.Partner.Company.CompanyName

Inside my _AddOrderBy() I have this:

Partner p = null;
            Company comp = null;
            order = query.Inner.JoinAlias(x => x.Partner, () => p)
                .Inner.JoinAlias(x => x.Company, () => comp)
                .OrderBy(x => comp.CompanyName);

But this gives me a run time exception stating that I have duplicate key (referring to Partner) in the criteria. I can see that this is conflicting with my eager fetching. My questions is:

How do I add an "order by" so it works with my Fetching.

Solution

The beauty of using an Alias in QueryOver is that you don't have to use Fetch or JoinAlias in your _AddOrderBy() method again if the Join happens in the query already. You only need to declare the Alias with the same name.

Therefore your _AddOrderBy() can just look like this:

Partner p = null;
Company comp = null;
order = query
    .Inner.JoinAlias(x => p.Company, () => comp) // you can use p here if it was used in the query before
    .OrderBy(x => comp.CompanyName);

The reason this works is this: If you put the whole code into one method it will obviously work. Splitting it into two methods still works, because Partner p is not a reference to an object in memory but an Alias that is simply translated into a string for the SQL query.