Having trouble with foreign key in entity, can't track because the FK is already part of another object

Question

Scenario: I have an entity that is central to the business, let's call it Company. Entity Foo has FK CompanyID, as does entity Bar.

If, within the same context, I retrieve Foo and create an instance of Bar, then try _context.Foo.Update(instanceOfFoo), then I get an InvalidOperationException:

The instance of entity type 'Company' cannot be tracked because another instance with the same key value for {'CompanyId'} is already being tracked. When attaching existing entities, ensure that only one entity instance with a given key value is attached.

CompanyID is part of many entities, removing it is a non-starter.

I'm new-ish to EF Core, and would appreciate any suggestions.

Answer 1

Hi DavidCraig-4984,
According to your description, maybe your context is being shared by multiple requests which means that the entity you're editing has been tracked already.
You can try to detach an object that has been attached to the context via setting the state to Detached.
Code likes below:

Context.Entry(entity).State = EntityState.Detached  

If you want to load entities from the database without fully attaching them to the context (without change tracking), you can use AsNoTracking as JaliyaUdagedara saide.
Here are some similar threads you can refer to.
The instance of entity type cannot be tracked because another instance with the same key value for {'Id'} is already being tracked
instance of entity type cannot be tracked because another instance with same key value is tracked
Best Regards,
Daniel Zhang

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