This question has been asked before in earlier versions of MVC. There is also this blog entry about a way to work around the problem. I'm wondering if MVC3 has introduced anything that might help, or if there are any other options.

In a nutshell. Here's the situation. I have an abstract base model, and 2 concrete subclasses. I have a strongly typed view that renders the models with EditorForModel(). Then I have custom templates to render each concrete type.

The problem comes at post time. If I make the post action method take the base class as the parameter, then MVC can't create an abstract version of it (which i would not want anyways, i'd want it to create the actual concrete type). If I create multiple post action methods that vary only by parameter signature, then MVC complains that it's ambiguous.

So as far as I can tell, I have a few choices on how to solve this proble. I don't like any of them for various reasons, but i will list them here:

  1. Create a custom model binder as Darin suggests in the first post I linked to.
  2. Create a discriminator attribute as the second post I linked to suggests.
  3. Post to different action methods based on type
  4. ???

I don't like 1, because it is basically configuration that is hidden. Some other developer working on the code may not know about it and waste a lot of time trying to figure out why things break when changes things.

I don't like 2, because it seems kind of hacky. But, i'm leaning towards this approach.

I don't like 3, because that means violating DRY.

Any other suggestions?

Edit:

I decided to go with Darin's method, but made a slight change. I added this to my abstract model:


                    
                    

                        
                        asp.net-mvc
                        
                        asp.net-mvc-3
                        
                        polymorphism
                        
                        model-binding
                        
                    

                    

                        
                        
                        
                        
                        
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