DevForce Community Forum : POCO Merge Failure after Save

POCO Merge Failure after Save : Yes, the correct entity is updated...

Wed, 08 Sep 2010 12:07:10 -700

Author: rhaney
Subject: 2134
Posted: 08-Sep-2010 at 12:07pm

Yes, the correct entity is updated during the save procedure in my PocoSaveAdapter class.

I can retrieve these POCO objects, modify them at the client, verify the entity state has changed, and persist the changes via the SaveChanges method. At some point after the changes have been saved, the EM throws an exception on the client side (see the above exception).

I have a method defined as follows:

public void UpdateCustomField(CustomField current, CustomField original)

If I set a breakpoint at the beginning of this method, both "current" and "original" are fully populated objects, with the same ID. This method executes without exceptions. After updating and receiving the exception, if I restart my application I can pull up the entity and verify the changes were persisted.

The DevForce internal post save client-side merge operation is failing for POCO objects only. If I don't modify a POCO object, everything works as expected.

It might be worth noting that I couldn't get an EntityServerPocoSaveAdapter implementation to be discovered, but the convention based approach outlined in the wiki at http://drc.ideablade.com/xwiki/bin/view/Documentation/POCOSupportInDevForce worked.

I'd prefer the EntityServerPocoSaveAdapter approach, due to the BeforeSave and AfterSave overrides.

POCO Merge Failure after Save : Have you initialized the value...

Wed, 08 Sep 2010 11:28:20 -700

Author: davidklitzke
Subject: 2134
Posted: 08-Sep-2010 at 11:28am

Have you initialized the value of the id field?

POCO Merge Failure after Save : FYI, this exception is raised...

Tue, 07 Sep 2010 14:17:21 -700

Author: rhaney
Subject: 2134
Posted: 07-Sep-2010 at 2:17pm

FYI, this exception is raised in 6.0.4 and 6.0.5.

POCO Merge Failure after Save : I've created a simple POCO...

Tue, 07 Sep 2010 14:15:11 -700

Author: rhaney
Subject: 2134
Posted: 07-Sep-2010 at 2:15pm

I've created a simple POCO class to support user defined fields in my DevForce application. I can get instances of the POCO class into the UI, and push updates back to the server via the SaveChanges method, but an exception is always raised on the client side after my PocoSaveAdapter executes.

My POCO object is pretty simple:

CustomField

int : Id

string : Name

string : Value

Id is marked with the [Key] attribute.

Is there something I am missing?

Here is the exception:

IdeaBlade.EntityModel.EntityManagerSaveException: EntityManager merge failure: Object reference not set to an instance of an object. ---> System.NullReferenceException: Object reference not set to an instance of an object.
   at IdeaBlade.Core.MemberInfoFns.BuildPropertySet(PropertyInfo property)
   at IdeaBlade.EntityModel.EntityProperty.get_SetFunc()
   at IdeaBlade.EntityModel.PocoEntityWrapper.CopyValues(Object sourceEntity, Object destEntity)
   at IdeaBlade.EntityModel.PocoEntityWrapper.ReplaceCurrentOnLoadCore(EntityWrapper sourceWrapper)
   at IdeaBlade.EntityModel.EntityWrapper.ReplaceCurrentOnLoad(EntityWrapper sourceEntity)
   at IdeaBlade.EntityModel.EntityWrapper.LoadEntity(EntityWrapper sourceWrapper, MergeStrategy mergeStrategy)
   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.<>c__DisplayClass1.b__0(EntityWrapper sourceWrapper)
   at System.Linq.Enumerable.WhereSelectEnumerableIterator`2.MoveNext()
   at System.Collections.Generic.List`1..ctor(IEnumerable`1 collection)
   at System.Linq.Enumerable.ToList[TSource](IEnumerable`1 source)
   at IdeaBlade.EntityModel.EntityMerger.Merge(IEnumerable`1 sourceEntityWrappersGroupedByType, NavigationContext context)
   at IdeaBlade.EntityModel.EntityMerger.Merge(EntityManager targetManager, IEnumerable`1 sourceEntityWrappersGroupedByType, MergeStrategy mergeStrategy, MergeType mergeType)
   at IdeaBlade.EntityModel.EntityManager.SaveEntitiesPostProcessing(SaveWorkState workState)
   --- End of inner exception stack trace ---
   at IdeaBlade.EntityModel.AsyncProcessor`1.<>c__DisplayClass2.<.ctor>b__0(TArgs args)
   at IdeaBlade.EntityModel.AsyncProcessor`1.Signal()
   at IdeaBlade.EntityModel.AsyncProcessor`1.b__5(Object x)

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