Question

What’s the best way to validate a model when using mvc with repository?
I look for examples but I didn’t find any that is exactly what I need.

Assuming I have a model with 5 properties.. 3 of them with dataannotations.. and I have some validations that I need to check in database before insert.

I need something like ‘User.IsValidToInsert’ to check if its valid. But I want to use ‘ModelState.IsValid’ too, cause I dont want to check manually all properties with dataannotations in ‘IsValidToInsert’.

How can I do this? Should I set validations that access database in ‘IsValidToInsert’? Should I pass ‘User’ and ‘ModelState’ like parameters to repository class?

Answer 1

You should be using a View Model that is specific to the view. If you have a Create action to create a Product, create a ProductCreate view model. You can put the data annotations (or Fluent Validation, etc.) that is specific to creating a product. This will be the model for your View/Controller. If you have an Edit page, then create a ProductEdit view model.

Now if you have additional logic (such as validating if a user already exists, then you should put that in a service layer. Your controller should be as simple as possible. You post your view model, convert it to a domain model and pass it to the service layer if necessary.

[HttpPost]
public ActionResult Create(ProductCreate model)
{
    // simple validations
    if( !ModelState.IsValid )
    {
        return View(model);
    }

    // Domain Model / Entity
    Product product = // create a product from your model here

    // service layer
    ProductService.Add(product);

    return RedirectToAction("Index");
}