You could use a custom model binder. Let's take an example.
Model:
public class MyViewModel
{
public IList<BaseClass> Children { get; set; }
}
public abstract class BaseClass
{
public int Id { get; set; }
[HiddenInput(DisplayValue = false)]
public string ModelType
{
get { return GetType().FullName; }
}
}
public class Derived1 : BaseClass
{
public string Derived1Property { get; set; }
}
public class Derived2 : BaseClass
{
public string Derived2Property { get; set; }
}
Controller:
public class HomeController : Controller
{
public ActionResult Index()
{
var model = new MyViewModel
{
Children = new BaseClass[]
{
new Derived1 { Id = 1, Derived1Property = "prop1" },
new Derived2 { Id = 2, Derived2Property = "prop2" },
}
};
return View(model);
}
[HttpPost]
public ActionResult Index(MyViewModel model)
{
// everything will be fine and dandy here
...
}
}
View (~/Views/Home/Index.cshtml):
@model MyViewModel
@using (Html.BeginForm())
{
for (int i = 0; i < Model.Children.Count; i++)
{
@Html.EditorFor(x => x.Children[i].ModelType)
<div>
@Html.EditorFor(x => x.Children[i].Id)
@Html.EditorFor(x => x.Children[i])
</div>
}
<button type="submit">OK</button>
}
Editor template for the Dervied1 type (~/Views/Home/EditorTemplates/Derived1.cshtml):
@model Derived1
@Html.EditorFor(x => x.Derived1Property)
and the editor template for the Dervied2 type (~/Views/Home/EditorTemplates/Derived2.cshtml):
@model Derived2
@Html.EditorFor(x => x.Derived2Property)
Now all that's left is a custom model binder that will use the hidden field value to instantiate the proper type in the collection:
public class BaseClassModelBinder : DefaultModelBinder
{
protected override object CreateModel(ControllerContext controllerContext, ModelBindingContext bindingContext, Type modelType)
{
var typeValue = bindingContext.ValueProvider.GetValue(bindingContext.ModelName + ".ModelType");
var type = Type.GetType(
(string)typeValue.ConvertTo(typeof(string)),
true
);
var model = Activator.CreateInstance(type);
bindingContext.ModelMetadata = ModelMetadataProviders.Current.GetMetadataForType(() => model, type);
return model;
}
}
which will be registered in Application_Start:
ModelBinders.Binders.Add(typeof(BaseClass), new BaseClassModelBinder());
