well now i feel dumb and bad. first off, i wasnt able to get your
example to compile, but it was probably more due to my lack of
knowledge around sqlite than anything. so i decided to write another
unit test of my own that basically looks like this:
Dim flRepos As New Repository(session)
Dim id As Integer = 1
Dim product = flRepos.Query(Of Product)(Function(p As Product)
p.Id = id).FirstOrDefault()
Assert.AreEqual(id, product.Id)
and it passed. so the problem doesnt look like its in fluent
nhibernate from that stand point. But if you look up at my original
question, you'll see that I'm trying to wrap the fluent nhibernate
repository in my own generic repository. When I then call the GetById
method, which I believe does the same thing as what I have in the code
in this message, I get an exception trying to cast Int to Product.
Does that make sense?
On Jan 7, 5:42 pm, "James Gregory" <jagregory....@gmail.com> wrote:
> Josh: I've tried reproducing your problem, but I haven't been able to. I
> created a Product class, a ProductMap, and then wrote a little unit test to
> see if it worked, and it did.
> <TestFixture()> _
> Public Class VbLinqTests
> Private _source As ISessionSource
>
> <SetUp()> _
> Public Sub CreateDatabase()
> Dim properties As IDictionary(Of String, String) = New
> SQLiteConfiguration() _
> .UseOuterJoin() _
> .InMemory() _
> .ToProperties()
>
> _source = New
> SingleConnectionSessionSourceForSQLiteInMemoryTesting(properties, New
> TestModel())
> _source.BuildSchema()
> End Sub
>
> <Test()> _
> Public Sub TestLinq()
> Dim flRepos As New Repository(_source)
>
> flRepos.Save(New Product())
> flRepos.Save(New Product())
> flRepos.Save(New Product())
> flRepos.Save(New Product())
>
> Dim product As Product = flRepos.Query(Of Product)(Function(p As
> Product) p.Id > 1).ToList().FirstOrDefault
>
> Assert.NotNull(product)
> End Sub
> End Class
>
> Can you try running that yourself to see what happens?
>
> On Tue, Jan 6, 2009 at 11:00 PM, Josh Pollard <j...@glmotorsports.net>wrote:
>
>
>
> > I did some more investigating and it looks like Linq2NHib only pukes
> > when using lambda expressions in VB. The following works:
>
> > Dim product = (From p In session.Linq(Of Product)() _
> > Where p.Id = testId _
> > Select p).FirstOrDefault()
>
> > Obviously that isn't using Fluent NHib at all. So the question is, how
> > do I use Fluent NHib without using lambdas? I think the problem is
> > that I don't know what us as my "in"
>
> > Any ideas on how to cram a full linq query into the Fluent NHib Query
> > method?
>
> > On Jan 5, 3:31 pm, "Jeremy Skinner" <jer...@jeremyskinner.co.uk>
> > wrote:
> > > I can't be certain as I haven't got VB installed to test this, but it
> > > certainly appears to be the case. Linq to NHibernate's unit tests are all
> > in
> > > C# so it doesn't surprise me that the differences in VB's expression
> > trees
> > > have been missed.
>
> > > 2009/1/5 RalyDSM <j...@glmotorsports.net>
>
> > > > so I guess i need to take this problem to the linq-to-nhibernate
> > > > guys...
>
> > > > On Jan 5, 3:19 pm, "Jeremy Skinner" <jer...@jeremyskinner.co.uk>
> > > > wrote:
> > > > > Yep, you'll notice there's no where clause on the query. Its loading
> > the
> > > > > entire table then performing an in-memory linq query.
>
> > > > > 2009/1/5 RalyDSM <j...@glmotorsports.net>
>
> > > > > > are you SURE about the compile thing? When I turn on the show_sql
> > > > > > property in NHibernate this is the query that is written:
> > > > > > SELECT this_.Id as Id2_0_, this_.Title as Title2_0_ FROM [Product]
> > > > > > this_
>
> > > > > > On Jan 5, 3:04 pm, "Jeremy Skinner" <jer...@jeremyskinner.co.uk>
> > > > > > wrote:
> > > > > > > I don't think this is an issue with the Repository, rather an
> > issue
> > > > with
> > > > > > > Linq to NHibernate. The VB and C# compilers (unhelpfully) create
> > > > > > expression
> > > > > > > trees differently. My guess is the Linq to NHibernate code does
> > not
> > > > parse
> > > > > > VB
> > > > > > > expression trees correctly (I can't verify this as I don't have
> > VB
> > > > > > installed
> > > > > > > on this machine).
>
> > > > > > > You don't want to be calling where.Compile() - this causes the
> > > > expression
> > > > > > > tree to be compiled into a delegate and can no longer be
> > translated
> > > > into
> > > > > > SQL
> > > > > > > - instead this ends up loading the entire table into your
> > application
> > > > and
> > > > > > > then doing an *in-memory* filter (bypassing Linq to NHibernate's
> > > > > > expression
> > > > > > > tree parsing).
> > > > > > > Jeremy
> > > > > > > 2009/1/5 James Gregory <jagregory....@gmail.com>
>
> > > > > > > > That's very interesting. Unfortunately, the bits in the
> > Framework
> > > > > > > > project are rather neglected, so there may very-well be a bug
> > in
> > > > > > > > there. I need to investigate this before I can pass judgement
> > > > though.
>
> > > > > > > > On 1/5/09, RalyDSM <j...@glmotorsports.net> wrote:
>
> > > > > > > > > I think I might have found a bug, but I'm not really sure. It
> > > > could
> > > > > > be
> > > > > > > > > a syntax error on my part, but the compiler isn't catching.
> > > > Anyway,
> > > > > > > > > here is what I'm trying to do. Basically I've written my own
> > > > > > > > > repository class that essentially just wraps the Fluent
> > > > Repository
> > > > > > > > > class. So here is the relevant code:
>
> > > > > > > > > Public Class GenericRepository(Of T As IHasIntId)
>
> > > > > > > > > Private _fluentRepos As
> > > > FluentNHibernate.Framework.IRepository
>
> > > > > > > > > Public Sub New(ByVal FluentRepository As
> > > > > > > > > FluentNHibernate.Framework.IRepository)
> > > > > > > > > _fluentRepos = FluentRepository
> > > > > > > > > End Sub
>
> > > > > > > > > Private Sub New()
>
> > > > > > > > > End Sub
>
> > > > > > > > > Public Function GetById(ByVal Id As Integer) As T
>
> > > > > > > > > Return Query(Function(x As T) (x.Id =
> > Id)).FirstOrDefault
>
> > > > > > > > > End Function
>
> > > > > > > > > Public Function Query(ByVal w As Expression(Of
> > System.Func(Of
> > > > T,
> > > > > > > > > Boolean))) As IList(Of T)
>
> > > > > > > > > Return _fluentRepos.Query(Of T)(w).ToList()
>
> > > > > > > > > End Function
>
> > > > > > > > > End Class
>
> > > > > > > > > Then I wrote two unit tests, one that would pass in an
> > > > > > > > > InMemoryRepository and one that would use an actual
> > NHibernate
> > > > > > session
> > > > > > > > > to hit the real database.
>
> > > > > > > > > here they are:
>
> > > > > > > > > <TestMethod()> Public Sub InMemoryTest()
>
> > > > > > > > > Dim inmemRepos As New InMemoryRepository()
>
> > > > > > > > > Dim p As New Product()
> > > > > > > > > Dim id As Integer = 5
> > > > > > > > > p.Id = id
> > > > > > > > > p.Title = "my product"
>
> > > > > > > > > inmemRepos.Save(p)
>
> > > > > > > > > Dim genRepos As New GenericRepository(Of
> > > > Product)(inmemRepos)
>
> > > > > > > > > Dim foundP = genRepos.GetById(id)
>
> > > > > > > > > Assert.AreEqual(p.Title, foundP.Title)
>
> > > > > > > > > End Sub
>
> > > > > > > > > <TestMethod()> Public Sub DatabaseTest()
>
> > > > > > > > > Dim session =
> > > > NHibernateSessionManager.Instance.GetSession()
>
> > > > > > > > > Dim flRepos As New Repository(session)
> > > > > > > > > Dim genRepos As New GenericRepository(Of
> > > > Product)(flRepos)
>
> > > > > > > > > Dim id As Integer = 1
>
> > > > > > > > > Dim p = genRepos.GetById(id)
>
> > > > > > > > > Assert.IsNotNull(p)
> > > > > > > > > Assert.AreEqual(id, p.Id)
>
> > > > > > > > > End Sub
>
> > > > > > > > > The InMemoryTest passed, and the DatabaseTest failed. The
> > > > exception
> > > > > > > > > from the DatabaseTest was a type conversion, from int to
> > product
> > > > (or
> > > > > > > > > maybe the other way around.) I was able to "fix" it though.
> > In
> > > > the
> > > > > > > > > Fluent NHibernate code I changed the Query method on the
> > > > Repository
> > > > > > > > > class from:
>
> > > > > > > > > return _session.Linq<T>().Where(where).ToArray();
>
> > > > > > > > > to
>
> > > > > > > > > return _session.Linq<T>().Where(where.Compile()).ToArray();
>
> > > > > > > > > Now both tests pass. All of the unit tests in the Fluent
> > > > NHibernate
> > > > > > > > > project pass either way.
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