EF4 - Context.Entry isn't available to change

问题:

I use an EDMX schema as my context. On a previous project where I didn't use a schema, I could change the entity state like this:

public void SaveProduct(Product product)
{
    if (product.ProductID == 0)
        context.Products.Add(product);
    else
        context.Entry(product).State = EntityState.Modified;
    context.SaveChanges();
}

But in this project, I don't see .Entry in my intellisense (and it won't suggest a namespace reference if I just type it in).

I tried to modify an entity ans save it. It worked properly.

So my two questions are: - Why is .Entry not in my intellisense anymore? - Do we really need to change the entity state with a persistent Context or can we rely on .Net to do that properly?

回答1:

I guess previously you used DbContext API but now you are using ObjectContext API - those are two different ways to use EF and each have its own way to do it. Check if you have this (ObjectContext API):

context.ObjectStateManager.ChangeObjectState(product, EntityState.Modified);

To your second question - you need to attach entity and set state if you are working with detached scenario (your entity instance is not loaded by the same context instance as it is saved).