domain service - server side update

I have a silverlight 4 RIA Domain Service. In one particular method I need to change one value in the database (among other things of course). To do this I get the entity, change the one value, then I need to save that change back to the DB.

I've tried calling the entity's generated update function, which just calls this.ObjectContext.myEntity.AttachAsModified(myENtity); but the change never gets back to the database.

How do I save values from the sever side (ie. the cli开发者_如何转开发ent never had this data)?

You should know that the UpdateXXX method doesn't actually submit the changes to the database - that only happens a bit later. knowing this, we can change the default implementation of the UpdateXXX method: (I'm assuming XXX == Product here)

    public void UpdateProduct(Product currentProduct)
    {
        this.ObjectContext.Products.AttachAsModified(currentProduct, this.ChangeSet.GetOriginal(currentProduct));
    }

to

    public void UpdateProduct(Product currentProduct)
    {
        // This line only reattach the entity back to EF context, it doesn't submit changes yet
        this.ObjectContext.Products.AttachAsModified(currentProduct, this.ChangeSet.GetOriginal(currentProduct));

        currentProduct.SomeProperty = "SomeChange"; // This change is going to be submitted later
    }

Turns out, attaching the object before or after the change makes no difference. The missing peice was :

this.ObjectContext.SaveChanges();