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Add child to existing parent record in entity framework.

Answer 1

A:

Presumably it's complaining about the childResource not being in the added state. You added it to the edge object that is in the added state.

Can you try flipping the way you set that association round:-

public void  AddChildResource(int parentResourceId, Resource childResource)
{
    Resource parentResource = repository.GetResource(parentResourceId);

    ResourceEdge inEdge = new ResourceEdge();
    // inEdge.ToResource = childResource;  <-- don't do this

    parentResource.ToEdges.Add(inEdge);
    childResource.FromEdges.Add(inEdge);  // try this instead

    repository.SaveResource(parentResource);
}

Hightechrider 2010-04-12 05:05:52

Hello, I get the same error both ways :(. At this point, I'm considering never to use EF for my other projects.

Shawn Mclean 2010-04-13 02:54:29

Were all of these objects loaded from the same object context? How is your ObjectContext lifetime managed?

Hightechrider 2010-04-13 03:33:01

And can you post the EF/VS version number and EDMX file if possible too?

Hightechrider 2010-04-13 04:01:51

Not sure what the ObjectContext lifetime is. But from the code above in the Service "AddChildResource', The childResource entity parameter was created from code based on information gathered from the user. The parentResource comes straight from the repository database via the function GetResource(int) in the DAL.

Shawn Mclean 2010-04-13 17:24:12

Answer 2

+1 A:

Ah, it's actually very simple, once you think about it.. What you're trying to do it add the resource to the data context, even though this resource object was received from the database in the first place. So the error is not complaining about your child objects, but about your parent object! :)

Basically if you comment the first line in the SaveResource() method it should just work fine! E.g.:

public void SaveResource(Resource resource)
{
    // context.AddToResources(resource); //Should also add children.
    context.SaveChanges();
}

Or just move the AddChildResource method to your DAL:

public void AddChildResource(int parentResourceId, Resource childResource)
{
    Resource parentResource = repository.GetResource(parentResourceId);

    ResourceEdge inEdge = new ResourceEdge();
    inEdge.ToResource = childResource;

    parentResource.ToEdges.Add(inEdge);

    context.SaveChanges();
}

Artiom Chilaru 2010-04-19 06:20:44

Answer 3

A:

We have already posted a recommendation on MSDN concerning code similar to yours.
Was it helpful?

Devart 2010-04-19 12:02:44

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Add child to existing parent record in entity framework.

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