janhartmann janhartmann - 1 month ago 10
C# Question

The entity type <type> is not part of the model for the current context

I am getting into the Entity Framework, but I am unsure if I am missing a critical point in the code-first approach.

I am using a generic repository pattern based on the code from https://genericunitofworkandrepositories.codeplex.com/ and have created my entities.

But when I try to access or modify the entity I run into the following:


System.InvalidOperationException: The entity type Estate is not part
of the model for the current context.


It happens when I am trying to access it from my repository:

public virtual void Insert(TEntity entity)
{
((IObjectState)entity).ObjectState = ObjectState.Added;
_dbSet.Attach(entity); // <-- The error occurs here
_context.SyncObjectState(entity);
}


The database (./SQLEXPRESS) is created just fine, but the entities (tables) is just not created on startup.

I am wondering if I need to explicit set the mapping of the entities? Is EF not able to this by its own?

My Entity is:

public class Estate : EntityBase
{
public int EstateId { get; set; }
public string Name { get; set; }
}


My context is as so:

public partial class DimensionWebDbContext : DbContextBase // DbContextBase inherits DbContext
{
public DimensionWebDbContext() :
base("DimensionWebContext")
{
Database.SetInitializer<DimensionWebDbContext>(new CreateDatabaseIfNotExists<DimensionWebDbContext>());
Configuration.ProxyCreationEnabled = false;
}

public new IDbSet<T> Set<T>() where T : class
{
return base.Set<T>();
}

}


Is there any specific reason why this error occurs? I have tried enable migrations and enable automatic migrations without any help either.

Answer

Put this in your custom DbContext class:

protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
    modelBuilder.Entity<Estate>().ToTable("Estate");
}

If your tables are not created on startup, this is why. You need to tell the DbContext about them in the OnModelCreating method override.

You can either do custom per-entity mappings here, or separate them out into separate EntityTypeConfiguration<T> classes.

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