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c#.netentity-frameworkentity-framework-6poco

The item with identity [x] already exists in the metadata collection. How do I fix that?

I'm using Entity Framework 6, with POCO and fluent-API and I've noticed an annoying bug.

If I have an entity called MyEntity and this entity has a property called MyProp, that makes it impossible to create an entity called MyEntity_MyProp.

Exception:

The item with identity 'MyEntity_MyProp' already exists in the metadata collection.\r\nParameter name: item

The error immediately goes away if I rename any of the entities, or rename the properties.

The "bug" is obvious: the key [EntityName]_[PropertyName] must be unique in the metadata collection.

Screenshot:

Image

I'm migrating a huge Entity Framework model with 390+ classes from EF 4, database first, to EF 6, code first, with fluent-API. It's out of question to rename the entities or the tables.

How do I solve that?

EDIT

This SO question doesn't have anything to do with my problem: The item with identity 'Id' already exists in the metadata collection. Parameter name: item

Solution

  • It's a known bug. It's currently scheduled to be fixed in an arbitrary future version, that is, it's not in the road-map yet.

    Source: https://entityframework.codeplex.com/workitem/2084

    EDIT:

    According to @Anthony, this was fixed in v6.1.3