DataAnnotation Validations and Custom ModelBinder

Question

I\'ve been running some experiments with ASP.NET MVC2 and have run into an interesting problem.

I\'d like to define an interface around the objects that will be used

Answer 1

I had the same issue. The answer is instead of overriding BindModel() in your custom model binder, override CreateModel()...

protected override object CreateModel(ControllerContext controllerContext, ModelBindingContext bindingContext, System.Type modelType)
{
    if (modelType == typeof(IPhoto))
    {
        IPhoto photo = new PhotoImpl();
        // snip: set properties of photo to bound values
        return photo;
    }

    return base.CreateModel(controllerContext, bindingContext, modelType);
}

You can then let the base BindModel class do its stuff with validation :-)