Extending and Customizing Code First Models in Entity Framework

Question

Here is an interesting article on extending and customizing code first models in EF. As far as the extending the object for insert is concerned, Rowan has made it very clear.

ModelCustomizer.RegisterModelCustomization(
    mb =>
    {
      mb.Entity<MyBizCustomer>();
    });

ModelCustomizer.RegisterTypeSubstitution<Customer, MyBizCustomer>();

var service = new CustomerService();
var customer = new MyBizCustomer { FirstName = "Jane", LastName = "Doe", IsVIP = true };
service.AddCustomer(customer);

Now, my problem is, if I want to use MyBizCustomer to query something with the extended model, how can I do that. How can I query the model if I want to get all customers where IsVIP = true ?

Is there any more elegant way to allow the developers extend the existing model instead of using some key-value pair concept to implement dynamic fields?

svick · Accepted Answer · 2014-12-12 19:59:20Z

1

You can use the OfTYpe LINQ method to filter to entities that are MyBizCustomers and then apply your additional filter:

query.OfType<MyBizCustomer>().Where(c => c.IsVip)

edited Dec 12, 2014 at 19:59

svick

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answered Dec 12, 2014 at 18:56

Rowan Miller

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1 Comment

Satyajit Over a year ago

I created the main query in the CustomerService.cs: public IQueryable<Customer> GetData() { var db = new CustomerStalkerContext(); var customer = ModelCustomizer.Create<Customer>(); var data = db.Customers; return data; } Not getting any output data. Am I doing something wrong here?

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