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.
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.
Apparently, this error is very generic, it could have a number of reasons. In my case, it was the following: The connection string (in Web.config) generated by the .edmx
was invalid. After almost a day of trying everything, I changed the connection string from the EF string to an ADO.NET string. This solved my issue.
For example, the EF string looks something like this:
<connectionStrings>
<add name="BlogContext"
connectionString="metadata=res://*/BloggingModel.csdl|
res://*/BloggingModel.ssdl|
res://*/BloggingModel.msl;
provider=System.Data.SqlClient
provider connection string=
"data source=(localdb)\v11.0;
initial catalog=Blogging;
integrated security=True;
multipleactiveresultsets=True;""
providerName="System.Data.EntityClient" />
</connectionStrings>
And the ADO.NET string looks like this:
<connectionStrings>
<add name="BlogContext"
providerName="System.Data.SqlClient"
connectionString="Server=.\SQLEXPRESS;Database=Blogging;
Integrated Security=True;"/>
</connectionStrings>