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POPolymorphic model binding
 

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    <p>This question has been <a href="https://stackoverflow.com/questions/4012217/asp-net-mvc-2-binding-to-abstract-model">asked before</a> in earlier versions of MVC. There is also <a href="http://blog.abodit.com/2010/02/asp-net-mvc-ambiguous-match/" rel="noreferrer">this blog entry</a> 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.</p> <p>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 <code>EditorForModel()</code>. Then I have custom templates to render each concrete type.</p> <p>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.</p> <p>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:</p> <ol> <li>Create a custom model binder as Darin suggests in the first post I linked to.</li> <li>Create a discriminator attribute as the second post I linked to suggests.</li> <li>Post to different action methods based on type</li> <li>???</li> </ol> <p>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.</p> <p>I don't like 2, because it seems kind of hacky. But, i'm leaning towards this approach.</p> <p>I don't like 3, because that means violating DRY. </p> <p>Any other suggestions?</p> <p>Edit: </p> <p>I decided to go with Darin's method, but made a slight change. I added this to my abstract model:</p> <pre><code>[HiddenInput(DisplayValue = false)] public string ConcreteModelType { get { return this.GetType().ToString(); }} </code></pre> <p>Then a hidden automatically gets generated in my <code>DisplayForModel()</code>. The only thing you have to remember is that if you're not using <code>DisplayForModel()</code>, you'll have to add it yourself.</p>
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