使用可以为空的复合外键进行关联修复时出现异常

Question

我有Pocos和可以为空的外键的问题.我有2个表(订单和产品),每个表都有一个复合主键(orderid,orderid2)和(productid,productid2)我在两个表之间设置了一个0,1 ..*关联.一个订单可以与0或1个产品相关.一个产品有*与他有关的订单.

如何崩溃:

• 使用CreateObject()创建新产品.
• 将新产品添加到实体集.
• 使用CreateObject()创建新订单.
• 将新订单添加到实体集.

当我向产品的订单列表添加订单时,它会崩溃尝试修复关联(在新订单上设置产品导航属性)

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]

崩溃代码:

            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");

例外:

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)

注意:它适用于entytobjects,它适用于自跟踪实体,如果键不是复合键或不可为空,它可以工作.

我做错了什么或者它是一个真正的错误？

Answer 1

我不得不纠正poco TT:

Chage the lines(381,441和475):

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

按行:

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