EF CF Read-Only version of an Entity

Question

I'm looking for a way to create a read only (or immutable) version of an entity that I will be using as a reference object. e.g.

class Order
{
   public int OrderId {get; private set;}

   public virtual Product ProductOrdered{get;set;}
   public int ProductId {get;set;}

   public int Quantity{get;set;}
}

class Product
{
    public int ProductId { get; set; }
    public string Name { get; set; }
    public string Category { get; set; }
}

in the example above Product is supposed to be used as a reference data. i.e. Product should not be modified by code using product as a reference in the Order.

Now, I realize one way to enforce that is to make all the setters as private and no one would be able to change Product...

class ProductReadOnly
{
    public int ProductId { get; private set; }
    public string Name { get; private set; }
    public string Category { get; private set; }
}

but somewhere in my app i'll like the admins to be able to create/modify products. So, I could use the class Product (with public setters)

Now the questions are (assuming I'm able to map Product & ProductReadOnly to the product table using Table attribute)

will i be able to use ProductReadOnly as a navigation property in the Order class?
Can I load Product & ProductReadOnly (same product) in the same data context?
is there an easier way to do it (Detached object?)
any issues with this approach?

Try to google or search over Stackoverflow you will a lot of similar questions and answers. — abatishchev, Mar 29 '13 at 02:26

score 2 · Answer 1 · answered Mar 29 '13 at 03:34

No need to keep two entities like your solution.You can override SaveChanges in your context and disable/enable edit/add for products like this.

    public override int SaveChanges()
    {
      if(currentUserIsNotAnAdmin){
      var entries= ObjectStateManager.GetObjectStateEntries(EntityState.Added |   
   EntityState.Modified).OfType<Product>() ;
        foreach(entry in entries){//or throw an error here
          this.Entry(entry).State=System.Data.EntityState.Unchanged
        }
      }
        return base.SaveChanges();
    }

here I have disabled saving changes for the product entity if the current user is not a admin. Or else you can throw an error if there is any entry modified/added of type Product

This looks correct, but feels like the wrong way to solve the problem. — ta.speot.is, Mar 29 '13 at 03:35
Thanks. Instead of depending on the logged in user I'd like this to be based on the functionality of the application. I'm trying to figure out a design based solution that can be applied across the board. — skywqr, Mar 29 '13 at 11:29

EF CF Read-Only version of an Entity

1 Answers1