Question

Similar to ‘Dynamic LINQ OrderBy‘ I would like to make a dynamic QueryOver-OrderBy. However, when I do this:

query.OrderBy(h => h.GetType().GetProperty(sort.Member).GetValue(h, null)).Asc

I get an exception which says:

Unrecognised method call in epression h.GetType().GetProperty(value(Domain.Model.Repository+<>c__DisplayClass15).sort.Member).GetValue(h, null)

Apparently, nHibernate has some trouble understanding what’s going on. Does anyone have an idea on how to solve this particular issue?

Answer 1

The solution in the linked question doesn’t work as there still is a problem when multiple entities are joined and sorting should be done on a combination of properties from different entities. The only practical solution I could think was to create a dictionary from sort.Member to a Projection.Property.

var dict = new Dictionary<string, string>();
dict.Add("sortMember", "entityAlias.Property");
var sortOn = dict[sort.Member];
query.OrderBy(Projections.Property(sortOn)).Asc;

This works quite well. The dictionary basically replaces the whole if-else construction and a simple loop adds the orderBy. I guess I can modify the filtering-part in a similar fashion, but haven’t had time to work on that part yet.