Question

Suppose I have classes Foo and Bar as follow:

public class Foo
{
public string F1 {set; get;}
public string F2 {set; get;}

public Bar ContainerBar {set; get;}
}

public class Bar
{
public string B1 {set; get;}
public string B2 {set; get;}

public List<Foo> Foos {set; get;}
}

Following linq query has errors saying that foo does not contain a property named F1.

var query = from foo in session.Linq<Foo>()
                 select foo.ContainerBar;

query = query.Where(foo => foo.F1 == "abcdef");

I know foo in second statement is really a Bar because query selects ContainerBar.

The question is know how can I add a dynamic where clause to query without changing origianl query? Final goal is to have sub-queries with linq-to-nhibernate.

Answer 1

var query = from foo in session.Linq<Foo>()
                 select foo.ContainerBar;

query = query.Where(foo => foo.F1 == "abcdef");

Your “query” object is now an IQueryAble of ContainerBar’s
So when you do the Where( foo => foo.F1 == “abcdef” ), it’s done on IQueryable, so no F1 property.

You should do:

var bars = from foo in session.Linq<Foo>()
            where foo.F1 == "abcdef"
            select foo.ContainerBar;

Or:

var q = session.Linq<Foo>();

// if some condition
q = q.Where( foo => foo.F1 == "abcdef" );

var bars = q.Select( foo => foo.ContainerBar );