Navigation property null ref exception

I have a couple of entities joined by navigation properties, Transaction and TransactionDescription.  In this case, TransactionDescription is the principal role (0..1) and Transaction is the dependent role (*).  Transaction has a composite key on it made up of three columns, however none of those columns/properties are part of the association (they're joined by TxCode on one and TxnCode on another).  The Edmx is completely valid as far as entity is concerned, and I've stripped away all developer involvement in a bare bones IdeaBlade 2-tier application consuming this edmx.  I've made sure that I can successfully query TransactionDescription, however Transaction blows chunks all over the place when I try a simple .FirstOrDefault()

Here's the stack trace
Object reference not set to an instance of an object.
   at IdeaBlade.EntityModel.Entity.GetValueRaw(DataEntityProperty property, EntityVersion version)
   at IdeaBlade.EntityModel.EntityWrapper.<GetValuesRaw>b__9(DataEntityProperty p)
   at System.Linq.Enumerable.<>c__DisplayClass12`3.<CombineSelectors>b__11(TSource x)
   at System.Linq.Enumerable.WhereSelectArrayIterator`2.MoveNext()
   at System.Linq.Buffer`1..ctor(IEnumerable`1 source)
   at System.Linq.Enumerable.ToArray[TSource](IEnumerable`1 source)
   at IdeaBlade.EntityModel.EntityWrapper.GetValuesRaw(IEnumerable`1 properties)
   at IdeaBlade.EntityModel.EntityWrapper.FindRelatedWrappers(EntityRelationLink relationLink, Boolean includeDeleted)
   at IdeaBlade.EntityModel.EntityWrapper.FindRelatedWrapper(EntityRelationLink relationLink, Boolean includeDeleted)
   at IdeaBlade.EntityModel.ScalarEntityReference`1.FindToEntity()
   at IdeaBlade.EntityModel.ScalarEntityReference`1.FixupReferences()
   at IdeaBlade.EntityModel.EntityWrapper.<FixupReferences>b__13(EntityReferenceBase eref)
   at IdeaBlade.Core.EnumerableFns.ForEach[T](IEnumerable`1 items, Action`1 action)
   at IdeaBlade.EntityModel.EntityWrapper.FixupReferences()
   at IdeaBlade.EntityModel.EntityWrapper.TrackChanged(EntityChangedEventArgs e)
   at IdeaBlade.EntityModel.EntityGroup.OnEntityChanged(EntityChangedEventArgs e)
   at IdeaBlade.EntityModel.EntityGroup.AddQueriedEntity(EntityWrapper wrapper)
   at IdeaBlade.EntityModel.EntityGroup.LoadEntity(EntityWrapper sourceWrapper, MergeStrategy mergeStrategy, Boolean& rowUpdated)
   at IdeaBlade.EntityModel.EntityMerger.MergeEntityCore(EntityWrapper sourceWrapper, EntityGroup targetEntityGroup)
   at IdeaBlade.EntityModel.EntityMerger.MergeEntity(EntityWrapper sourceWrapper, EntityGroup targetEntityGroup, NavigationContext context)
   at IdeaBlade.EntityModel.EntityMerger.MergeEntity(EntityWrapper sourceWrapper, NavigationContext context)
   at IdeaBlade.EntityModel.EntityQueryResult.UpdateDataSet(EntityDataBlock block, NavigationContext context)
   at IdeaBlade.EntityModel.EntityDataBlock.Resolve(EntityQueryResult helper)
   at IdeaBlade.EntityModel.EntityQueryResultCollection..ctor(DataQueryResultCollection dqResults, EntityManager entityManager, MergeStrategy mergeStrategy)
   at IdeaBlade.EntityModel.EntityManager.MergeAndReturnUsingCache(IEntityFinder finder, DataQueryResultCollection dqResults)
   at IdeaBlade.EntityModel.EntityManager.ProcessFetchedData(DataQueryResultCollection dqResults, IEntityFinder finder)
   at IdeaBlade.EntityModel.EntityManager.ExecuteFetch(IEntityFinder finder)
   at IdeaBlade.EntityModel.EntityQueryFinder.Execute()
   at IdeaBlade.EntityModel.EntityManager.ExecuteQueryCore(IEntityQuery query, Boolean isAsync)
   at IdeaBlade.EntityModel.EntityQuery`1.System.Linq.IQueryProvider.Execute[TResult](Expression expression)
   at System.Linq.Queryable.FirstOrDefault[TSource](IQueryable`1 source)
   at Testing.Client.MainWindow..ctor() in C:\Users\dpollot.MANNING-NAPIER\Documents\Visual Studio 2010\Projects\Testing\Testing.Client\MainWindow.xaml.cs:line 27

And here's an snippet of the csdl

<EntityType Name="PendingLongTransaction">
          <Key>
            <PropertyRef Name="SysDate" />
            <PropertyRef Name="SetNo" />
            <PropertyRef Name="LtRefer" />
          </Key>
...
</EntityType>
<EntityType Name="TransactionDescription">
          <Key>
            <PropertyRef Name="TxnCode" />
          </Key>
...
</EntityType>

<Association Name="FKPendingTxnTxnDescription">
          <End Type="OpenOrdersMaintenance.Data.PendingLongTransaction" Role="PendingLongTransaction" Multiplicity="*" />
          <End Type="OpenOrdersMaintenance.Data.TransactionDescription" Role="TransactionDescription" Multiplicity="0..1" />
          <ReferentialConstraint>
            <Principal Role="TransactionDescription">
              <PropertyRef Name="TxnCode" />
            </Principal>
            <Dependent Role="PendingLongTransaction">
              <PropertyRef Name="TxCode" />
            </Dependent>
          </ReferentialConstraint>
        </Association>

Any ideas what's going on?

Since you've stripped this down to a bare bones sample, would you be willing to zip it and send it to us?  If this application also exhibits the other problem you reported with an OutOfMemoery exception with navigation properties that would be great too.

You can send it to me - kimj at ideablade.com.  I don't need the database, as you say the EDMX, along with other nformation, should be sufficient.  If you also have any debug logs that will help too.

6.0.4 broke all my projects...

First, it seems that after updating, I have to remove all the references (to ideablade assemblies like IdeaBlade.EntityModel, IdeaBlade.Core, etc.) and re-add them.  Why is this??? (this will make upgrading an absolute nightmare).

Second, it appears you've gotten rid of PendingEntityResolved??

from my codegen:

                    //this.<#= navigationProperty.Name #>.PendingEntityResolved += (sender, args) => {
                    //    OnPropertyChanged(new PropertyChangedEventArgs("Properties"));
                    //    if (null != callback)
                    //        callback();
                    //};

which yields (for one specific entity) broken code:

                    //this.AssociationParent.PendingEntityResolved += (sender, args) => {
                    //    OnPropertyChanged(new PropertyChangedEventArgs("Properties"));
                    //    if (null != callback)
                    //        callback();
                    //};

I've gotten the project to build, but I'll have to go through and test to be sure that everything still works, and then I'll get to testing the functionality that prompted the upgrade in the first place... I would really like to know how we can circumvent breaking changes (in terms of assembly references) in the future.  Obviously I'll just need to be more diligent about reading the release notes before upgrading next time for the other errors...

This release seems to have "sorta fixed" one problem, and not fixed the other.

The problem that it's partially fixed was the misbehaving association between transaction and transaction description...
Here's my calling code:

            var plt = Context.EntityManager.PendingLongTransactions.FirstOrDefault();
            plt.LoadNavigationProperty("PendingTransactionDescription");
            var desc = plt.PendingTransactionDescription;

Here's the LoadNavigationProperty method:

        public override void LoadNavigationProperty(string propertyName)
        {
            switch(propertyName)
            {       
                case "PendingTransactionDescription":
                    this.EntityAspect.GetRelatedEntity<TransactionDescription>(EntityRelations.FKPendingTxnTxnDescription.Role1.Link);                   
                    break;           
            }
        }

It no longer throws a null reference exception, however neither side of the association in terms of navigation properties are returning results (I've tested to be sure that there are actually results for both sides of the association for a given record (and that it still works in EF).

The other problem (where the call to GetRelatedEntity<T>(...) never returns) has not been fixed by the upgrade.

We've disabled your "lazy loading" by default because we don't want developers grabbing navigation properties unintentionally and potentially sucking down our entire database while traversing the graph.  I've made sure this behavior can be overridden (by default we traverse your relations and set them to no load), but for the most part we're going to force our developers into calling the LoadNavigationProperty method so that they're explicit about the data they want.  Thus the reason we're calling GetRelatedEntity. 

We've also made codegen updates between versions 6.0.1 and 6.0.4, so you need to be sure to re-save your EDMX so that the code is regenerated.

We do our own code generation with our own t4 templates.  We're able to produce code that mirrors your code genned code, but allows us to do a number of additional things...

DevForce definitely still supports "asynchronous navigation" and the PendingEntityResolved and PendingEntityListResolved events

Those events used to be on EntityWrapper, which we're deriving from (since our objects derive from Entity).  They don't seem to be there anymore after I upgraded to 6.0.4.
Lines like this:

                    this.AssociationParent.PendingEntityResolved += (sender, args) =>
                    {
                        OnPropertyChanged(new PropertyChangedEventArgs("Properties"));
                        if (null != callback)
                            callback();
                    };
used to work, but no longer.  My co-worker is still using version 6.0.1. and I can navigate to the event handlers on his machine, but not mine.  Have they moved somewhere else??

I've sent the project to you again.

I've checked and double checked that this stuff works out the box using Entity Framework, and I'm definitely using the latest version of DevForce (6.0.4), so I'm really hoping that we can get this resolved, or you can at least point me in the right direction soon.  We'd prefer not to start implementing hackish workarounds to what should be functional navigation properties...

Hey ting,

I'm going to be troubleshooting this while Dave is away at VSLive next week.

I just talked to him and he mentioned that a mock .edmx file was created
from a SQL Server database that mimics our schema. He also mentioned that there were some differences between that .edmx and ours.

I was wondering if you could send me the associations from that file (in the SSDL and CSDL) so I could compare it to ours.

Thanks!