MVC - validate domain model

Question

I have a ASP.NET MVC application and want to have validation on both level - view model validation and domain model validation based on data annotation attributes. View Model validation works simple:

public class CustomerFormVM
{
    [Required]
    [Display(Name = "Name")]
    public string Name { get; set; }
    [Required]
    [Display(Name = "Street")]
    public string Street { get; set; }
    [Required]
    [Display(Name = "City")]
    public string City { get; set; }
    [Required]
    [Display(Name = "State")]
    public string State { get; set; }
}

and then call in controller:

        if (ModelState.IsValid)
        {

I have the same domain model class:

public class CustomerFormPoco
{
    [Required]
    [Display(Name = "Name")]
    public string Name { get; set; }
    [Required]
    [Display(Name = "Street")]
    public string Street { get; set; }
    [Required]
    [Display(Name = "City")]
    public string City { get; set; }
    [Required]
    [Display(Name = "State")]
    public string State { get; set; }
}

but how to validate it?

// viewmodel is CustomerFormVM object
var pocoModel = mapper.Map<CustomerFormPoco>(viewmodel);

if I don't check 'viewmodel' variable then I get 'pocoModel' variable with nullable Name, Street, City...

How to call validation and make decision depend on result?

Why not check the view model before you map it to the domain model? — Kyle Delaney, Dec 21 '17 at 18:01
I'd recommend you to assume the data is already validated in the Application Layer (with your view models), instead of validating everything again. Your domain should focus on validating business rules, not data. — Alisson Reinaldo Silva, Dec 21 '17 at 18:36
jQuery Validation can handle your validation of the viewmodel on the client side. Since you are only using `Required` attributes that should be simple. Then if it passes then you don't have to worry about validation on the server-side. — Grizzly, Dec 21 '17 at 19:12
This may be of use to you, and may explain why you are seeing nulls in your model even with `Required` annotations for strings - https://stackoverflow.com/questions/23939738/how-can-i-use-data-annotations-attribute-classes-to-fail-empty-strings-in-forms — ethane, Dec 21 '17 at 20:48

score 0 · Answer 1 · answered Dec 21 '17 at 18:08

How about something like this?

if (!string.IsNullOrEmpty(pocoModel.Name) && !string.IsNullOrEmpty(pocoModel.Street) && !string.IsNullOrEmpty(pocoModel.City) && !string.IsNullOrEmpty(pocoModel.State))
{
    // Code here
}

I'd probably do it with less redundancy like this:

string[] fields = new string[] { pocoModel.Name, pocoModel.Street, pocoModel.City, pocoModel.State };
bool isValid = true;
foreach (string field in fields)
{
    if (string.IsNullOrEmpty(field))
    {
        isValid = false;
        break;
    }
}
if (isValid)
{
    // Code here
}

don't like this approach. First at all, I don't want mix logic with validation. Secondly, I want to have validation inside class. Thirdly, I want to use data annotation attributes — Oleg Sh, Dec 21 '17 at 20:18

MVC - validate domain model

1 Answers1