Can not find out how to do this:

Suppose EntityA -> EntityB (1:n)

EntityA has a field (say, AvgLevel) and EntityB has a field (say, Level).

I want to fetch some EntityAs, and for each EntityA, prefetch those EntityBs that have EntityB.EntityAId == EntityA.Id (of course), and EntityB.Level > EntityA.AvgLevel.

?

since your relating a to b in the filter I would recommend

PrefetchPath.Add(AEntity.PrefetechBOnId);
PrefetchPath[0].Filter.Add((BFields.level > AFields.AvgLevel));
PrefetchPath[0].FilterRelations = new EntityRelationCollection();
PrefetchPath[0].FilterRelations.Add(new ARelations.BOnId);

jmeckley wrote:

since your relating a to b in the filter I would recommend

PrefetchPath.Add(AEntity.PrefetechBOnId);
PrefetchPath[0].Filter.Add((BFields.level > AFields.AvgLevel));
PrefetchPath[0].FilterRelations = new EntityRelationCollection();
PrefetchPath[0].FilterRelations.Add(new ARelations.BOnId);

Using the following code:

IPrefetchPath2 pp;
IPrefetchPathElement2 ppe;

pp = new PrefetchPath2((int)EntityType.EntityA);
ppe = pp.Add(EntityA.PrefetechPathEntityBs);
ppe.Filter.Add((EntityBFields.level > EntityAFields.AvgLevel));

// following line removed, FilterRelations is readonly
//ppe.FilterRelations = new EntityRelationCollection();

// removed 'new'
ppe.FilterRelations.Add(EntityA.Relations.EntityBUsingEntityAId);

... the ASP.NET server dies (stack overflow) so it's hard to tell what's going wrong. I'll have to create a standalone app and debug through it... unless someone has a better idea?

Edited : the server dies because of code that has nothing to do w/LLBLGen, after the correct query has returned successfully. So, question considered answered. Thanks!

Indeed, you should debug and see what hangs it. Also you should check the generated queries to see if something was generated in a wrong way, by setting some tracing switches, please check the manual "Using the generated code -> Troubleshooting and debugging"

Also please try the following line: ppe.FilterRelations.Add(EntityB.Relations.EntityAUsing...); Instead of: ppe.FilterRelations.Add(EntityA.Relations.EntityBUsingEntityAId);

EDIT: Glad it's solved.