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POSaving a ObjectContext depended object after two requests (EF/MVC 3)
 

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  1. POSaving a ObjectContext depended object after two requests (EF/MVC 3)
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    <p>Using EntityFramework, I am trying the following in combination with MVC 3.</p> <p>I have a <code>ObjectContext</code>, which is being initialized at the start of every request, and disposed at the end of the request. Much like a simple <code>UnitOfWork</code> implementation. Now think of having a <code>Order</code> class (EF generated), which is going to be initialised. I pass the <code>ObjectContext</code> to be used trough a overloaded constructor.</p> <pre><code>var order = new Order(myObjectContext); </code></pre> <p>Then inside the <code>Order</code> class this instance is kept (private field). After I set some properties of this <code>Order</code> instance (using the same <code>ObjectContext</code>). I want to put this instance in the Users' session because a second webpage is needed to populate some information before the order is ready to be saved.</p> <p>This is were I'm stuck, after the user submits the second webpage I retrieve the <code>Order</code> object from the session, set some more properties and hit <code>.SaveChanges()</code> on the <code>ObjectContext</code> references by the <code>Order</code> object. So the one that was made in the first request. I think this is required because during the first request (when the <code>Order</code> was created) some other entities are being added to one of the orders collection. So I have to use the same context again. The problem is that after hitting the <code>.SaveChanges()</code> the method returns no error or whatsoever, but the data is not saved in the database. Even the identity value does not change from zero. Nothing is being committed.</p> <p>When I first try to add the object to the collection:</p> <pre><code>this._context.Order.AddObject(this); this._context.SaveChanges(); </code></pre> <p>Please note this code is within a method, placed in a partial Order class. This time, at the <code>.AddObject()</code> I get the message:</p> <p><code>An entity object cannot be referenced by multiple instances of IEntityChangeTracker.</code></p> <p>I tried to detach the <code>Order</code> object from it's original context and reattach it to the context made in the second request but of course this is not working since one of the <code>Order</code> properties is a collection of other entities, retrieved and added in the first request, thus with the first <code>ObjectContext</code>.</p> <p>Probably I could overcome this issue by calling <code>.SaveChanges()</code> at the end of the first request. Then in the next request I would have to pull the order from the db with that request's <code>ObjectContext</code>. The thing is, I do not want to save the <code>Order</code> before the end of the second request.</p> <p>To me it looks like the <code>ObjectContext</code> which is kept with the <code>Order</code> instance in the session needs a 'connection-refresh'?</p>
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