CODEWITHSUNDEEP
entity-frameworkasp.net-core-mvcef-core-2.0
iPath ツ
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Reputation: 2488

Why IMutableEntityType.BaseType is null for entities that inherit directly from a base class?

I've defined the following classes:

public class DeletableEntity
{
    public bool IsDeleted { get; set; }
}

public class ClassA : DeletableEntity
{
}

public class ClassB : ClassA
{        
}

In the OnModelCreating I'm getting only entities that inherit from DeletableEntity like this:

    foreach (var entityType in builder.Model.GetEntityTypes())
    {
        if (typeof(DeletableEntity).IsAssignableFrom(entityType.ClrType) == true)
        {
            var et = entityType.BaseType;
        }
    }

Interestingly ClassA has entityType.BaseType == null but ClrType.BaseType clearly shows ClassA inherits from DeletableEntity:

enter image description here:

For ClassB entityType.BaseType is ClassA as expected:

enter image description here

Why first successor's parent class is being ignored? Is this by design?

PS: I'm using EF Core 2.2.

Upvotes: 1

Views: 544

Answers (1)

Ivan Stoev
Ivan Stoev

Reputation: 205849

It's because there is a difference between base class and base entity.

IEntityType represents class mapped as EF Core entity. The type BaseType property of IEnityType is also IEnityType. But in your example DeletableEntity is just a base class, not a base entity, so the property returns null.

Probably the best explanation is the property declaration:

//
// Summary:
//     Gets the base type of the entity. Returns null if this is not a derived type
//     in an inheritance hierarchy.
IEntityType BaseType { get; }

where "inheritance hierarchy" refers to EF Inheritance:

Inheritance in the EF model is used to control how inheritance in the entity classes is represented in the database.

and also Inheritance (Relational Database).

Upvotes: 4

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