Exception during association fixup with nullable composite foreign keys

Question

I have a problem with Pocos and nullable foreign keys . I have 2 tables (orders and products) each table have a composite primary key (orderid,orderid2) and (productid,productid2) And I have set a 0,1..* association between the two tables. One order can be related to 0 or 1 product. And one product has * orders related to him.

How to crash :

• Create a new product using CreateObject().
• Add the new product to then entityset.
• Create a new order usung CreateObject().
• Add the new Order to the entityset.

When I add an order to the product's orders list, it crashes trying to fixup the association (setting the product navigation property on the new order)

CREATE TABLE [dbo].[Products](
    [productid] [int] IDENTITY(1,1) NOT NULL,
    [productid2] [int] NOT NULL,
    [productname] [nchar](10) NULL,
 CONSTRAINT [PK_Products] PRIMARY KEY CLUSTERED 
(
    [productid] ASC,
    [productid2] ASC
)WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON) ON [PRIMARY]
) ON [PRIMARY]

CREATE TABLE [dbo].[Orders](
    [orderid] [int] NOT NULL,
    [orderid2] [int] NOT NULL,
    [ordername] [nchar](10) NULL,
    [productid] [int] NULL,
    [productid2] [int] NULL,
 CONSTRAINT [PK_orders] PRIMARY KEY CLUSTERED 
(
    [orderid] ASC,
    [orderid2] ASC
)WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON) ON [PRIMARY]
) ON [PRIMARY]

Code to crash :

            var product = context.CreateObject<Products>();
            context.Products.AddObject(product);
            var order = context.CreateObject<Orders>();
            context.Orders.AddObject(order);

            product.Orders.Add(order);
            if (order.Product != product) Console.WriteLine("error");

Exception :

System.Data.EntityException was unhandled
  Message=Unable to set field/property Product on entity type System.Data.Entity.DynamicProxies.Orders_A0290D8629F0336D278E5AEF2C0F2A91FF56726ED5E3A9FA668AC902696A8651. See InnerException for details.
  Source=System.Data.Entity
  StackTrace:
       at System.Data.Objects.Internal.PocoPropertyAccessorStrategy.SetNavigationPropertyValue(RelatedEnd relatedEnd, Object value)
       at System.Data.Objects.Internal.EntityWrapper`1.SetNavigationPropertyValue(RelatedEnd relatedEnd, Object value)
       at System.Data.Objects.DataClasses.EntityReference`1.AddToObjectCache(IEntityWrapper wrappedEntity)
       at System.Data.Objects.DataClasses.RelatedEnd.Add(IEntityWrapper wrappedTarget, Boolean applyConstraints, Boolean addRelationshipAsUnchanged, Boolean relationshipAlreadyExists, Boolean allowModifyingOtherEndOfRelationship, Boolean forceForeignKeyChanges)
       at System.Data.Objects.DataClasses.RelatedEnd.Add(IEntityWrapper wrappedEntity, Boolean applyConstraints)
       at System.Data.Objects.DataClasses.EntityCollection`1.Add(TEntity entity)
       at Proxies.CSharp.Program.Main(String[] args) in Program.cs:line 20
       at System.AppDomain._nExecuteAssembly(RuntimeAssembly assembly, String[] args)
       at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args)
       at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()
       at System.Threading.ThreadHelper.ThreadStart_Context(Object state)
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean ignoreSyncCtx)
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
       at System.Threading.ThreadHelper.ThreadStart()
  InnerException: System.NullReferenceException
       Message=Object reference not set to an instance of an object.
       Source=Proxies.CSharp
       StackTrace:
            at Proxies.CSharp.Orders.FixupProduct(Products previousValue, Boolean skipKeys) in Orders.cs:line 134
            at Proxies.CSharp.Orders.set_Product(Products value) in Orders.cs:line 106
            at System.Data.Entity.DynamicProxies.Orders_A0290D8629F0336D278E5AEF2C0F2A91FF56726ED5E3A9FA668AC902696A8651.SetBasePropertyValue(String , Object )
            at lambda_method(Closure , Object , String , Object )
            at System.Data.Objects.Internal.EntityProxyFactory.TrySetBasePropertyValue(Type proxyType, String propertyName, Object entity, Object value)
            at System.Data.Objects.Internal.EntityProxyFactory.<>c__DisplayClass8.<CreateBaseSetter>b__7(Object entity, Object value)
            at System.Data.Objects.Internal.PocoPropertyAccessorStrategy.SetNavigationPropertyValue(RelatedEnd relatedEnd, Object value)

Note : It works with entytobjects, it works with self-tracking entities, and It works if the key is not composite or not nullable.

Am I doing something wrong or it it a real bug ?

Answer 1

I had to correct the poco TT :

Chage the lines (381,441 and 475) :

<#=code.Escape(dependentProperty)#> = <#=code.Escape(navProperty)#>.<#=code.Escape(principalProperty)#>;

by the line :

<#=code.FieldName(dependentProperty)#> = <#=code.Escape(navProperty)#>.<#=code.Escape(principalProperty)#>;