Question

Hi
Given a list of strings I want to retrieve all items whose names contain one of the given strings.
for example- given {“foo”, “kuku”} I want to retrieve the employees “Corfoo”, “kuku maluku” and “kukufoo”.
I’ve tried the following, but got a null-reference exception(?)

query.Where(u => values.Any(v=> u.FullName.Contains(v)) );

The following produced a ‘Lambda expression not in scope’ exception.

query.Where(u => (values.Count(v => u.FullName.Contains(v)) > 0) );

any idea how this can be done?
I was thinking along the lines of iterating over the values collection and adding a new condition for each element.
problem is- the .Where() function is a conjunction (AND) and I need disjunction (OR)…
(I’m using nH 2.1.2 with Linq provider; hadn’t tried this on nH3.0 yet…)

Answer 1

If you are not limited to the Linq provider but also open to the ICriteria API, I suggest using the following:

List<string> fullnames = new List<string>() { "foo", "kuku" };
// prepare Query
var query = session.CreateCriteria(typeof(Employee));
// dynamically add Like-conditions combined with OR
Disjunction namesCriteria = Restrictions.Disjunction();
foreach (var name in fullnames)
{
    namesCriteria.Add(Restrictions.Like("FullName", name, MatchMode.Anywhere));
}
// add complete Disjunction to prepared query
query.Add(namesCriteria);
IList<Employee> list = query.List<Employee>();

I think trying that in NHibernate.Linq might be harder if not impossible. With NH 3.0 you could use QueryOver, which would get rid of the magic strings.