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I'm trying to wrap my head around dynamic nested predicate expressions. It's not going too well.

Basically I need to be able to create dynamic queries on a fixed set of properties but on a dynamic (and potentially unlimited) number of (nested) levels.

Taking a family tree as example, I should be able to write queries to get any one of these results:

  • find all parents who have children
  • find all parents who have children who's name starts with "k"
  • find all parents who have children, that has children that are born after 01/01/2013, that has children who's name is "John"
  • etc.

I can write something similar by hand which works just fine.

var pred = PredicateBuilder.True<db.Entity>();
pred = pred.And(n => 
    n.Children.Where(
        m => m.Children.Where(
            o => o.Name.Contains("John")
        ).Any()
    ).Any()
);

Question is how do I create the above code dynamically with mixed properties and operators on any number of nested levels?

Michael H. Pedersen
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  • i think this is an expert question. u should also post on the relevant page in Microsoft forums if u need an answer. multiplies your chances – Raghavan Feb 02 '13 at 07:02

0 Answers0