Generic Remote Validations in MVC 5

Question

I am developing an MVC 5 app using EF 6 database first approach. I have a certain validation which is required for fields in many of my models. I am using remote validation for validating them. Since it was being used in a lot of models so I am trying to go for a generic method.

For that matter I made an Interface named IEntity which includes all properties being used in my models. Then I did the following for my Validation method:

[HttpPost]
public JsonResult UniqueCheck<T>(T code) where T : class, IEntity
{
    MyEntities db = new MyEntities();
    if (db.Set<T>().Any(x=>x.S1 == code.S1))
    {
        return Json("Already Exists!");
    }
    else
    {
        return Json(true);
    }
}

And following is how I am calling the validation on properties in models:

[Remote("UniqueCheck", "Rules", HttpMethod = "POST")]

public string S1 { get; set; }

But the problem is that the validation is not working and when I checked in the browser console I got that the validation is actually going into the method but there was a 500(Internal Server Error) returned.

I know that the problem is with T written with method name because when I removed the generics and hardcoded my model name, it works fine.

I only want to use MVC's remote validation and I would be very happy to get this generic method working because otherwise it would be a copy/paste on a lot of locations.

Jungly

Do you have a stacktrace of the 500 ISE call? Knowing where it happened (e.g. ModelBinder, or routing or the method body itself) would help. – Laurenelaurens

I didn't get the stack trace.. I have seen the ISE call in the console window of browser.. I didn't even know that there was an error because VS was not showing any error. It wasn't just going into the validation. When I Go to "Inspect Element" in Chrome, I saw the error in console – Jungly

Bit unclear what your trying to achieve. The RemoteAttribute makes an ajax call and sends the name/value pair of the property to the controller method, in the case of property S1 it sends S1:someValue so you method nedds a parameter string S1 It does not send any other information (except the name/value pairs specified in AdditionalFields if you use it) so T is unknown. – Estaminet

I wanted to make a generic validation so that all my model properties S1 can use it. The error in console is "Failed to load resource: the server responded with a status of 500 (Internal Server Error)" – Jungly

Because T is undefined. The RemoteAttribute does not pass a class or interface to the method - just the name/value pair of the property. – Estaminet

how can i make it working?? or should i go for copy/paste it for each model? – Jungly

Make one method for each model. The only way you could make you generic method work would be to use AdditonalFields and render a hidden input in every view to store the class name then use reflection to initialize the class in your controller. Far more work than its worth. – Estaminet

Proposal: You can make a generic controller with the validations you want (generic type T on class level, not method level). Then you would create concrete versions just by inheritance (those would be basicaly empty classes). In the end, there would be one RulesController<T> and several empty children, e.g. UserRulesController, AdminRulesController and so on. – Laurenelaurens