modelbinder

namespace TC.ServicesPortal.ModelBinders
{
    public class InterfaceModelBinder : DefaultModelBinder
    {
        protected override object CreateModel(ControllerContext controllerContext, ModelBindingContext bindingContext, Type modelType)
        {
            var type = bindingContext.ModelType;

            if (type.IsInterface)
            {
                var fieldTypeKey = bindingContext.ModelName + ".FieldType";
                var assemblyFieldTypeKey = bindingContext.ModelName + ".FieldTypeAssembly";

                if (!String.IsNullOrEmpty(fieldTypeKey))
                {
                    var fieldType = ((string[])bindingContext.ValueProvider.GetValue(fieldTypeKey).RawValue)[0];
                    var assemblyFieldType = ((string[])bindingContext.ValueProvider.GetValue(assemblyFieldTypeKey).RawValue)[0];

                    modelType = Type.GetType(fieldType + ", " + assemblyFieldType);

                    var instance = Activator.CreateInstance(modelType);

                    bindingContext.ModelMetadata = ModelMetadataProviders.Current.GetMetadataForType(() => instance, modelType);

                    return instance;
                }
            }

            return null;
        }
    }
}