Question

I have an object in a simple test scenario that uses EF Code First and implements IValidatableObject. There’s some very simple logic that adds a validation error and returns it back. There are also other validations on the object.

However, when saving the object – while the attribute based validations work – the IValidatableObject interface never seems to fire. Debugger doesn’t step into it and the error never shows up with calling SaveChanges() or GetValidationErrors().

public class Customer : IValidatableObject {
[Key]
public int Id { get; set; }

[StringLength(50)]
[DisplayName("First Name")]

public string FirstName { get; set; }

[Required]
[DisplayName("Last Name")]
[StringLength(50)]
public string LastName { get; set; }

[Required]
[StringLength(100)]
public string Company { get; set; }

[StringLength(200)]
public string Email { get; set; }

[DisplayName("Credit Limit")]
public decimal CreditLimit { get; set; }

[DisplayName("Entered On")]
public DateTime? Entered { get; set; }


public virtual ICollection<Address> Addresses { get; set;  }


public Customer()
{
    Entered = DateTime.Now;
    CreditLimit = 1000.00M;

    Addresses = new List<Address>();
}

public IEnumerable<ValidationResult> Validate(ValidationContext validationContext)
{
    var results = new List<ValidationResult>();

    // add an error ALWAYS for testing - it doesn't show up
    // and the debugger never hits this code
    results.Add(new ValidationResult("Validate Added message",new [] { "Company" }));

    return results;
}

When I now try to add a customer and check for validation errors:

public void AddNewCustomer()
{
    Customer customer = new Customer();  

    context.Customers.Add(customer);

    customer.LastName = "Strahl";
    customer.FirstName = "Rick";
    customer.Entered = DateTime.Now;
    //customer.Company = "West Wind"; // missing causes val error

    var errorEntries = context.GetValidationErrors();
}

I get ONE validation error for the company, but nothing from the IValidatableObject which should ALWAYS fail.

Any idea why?

Answer 1

Quote from Jeff Handley’s Blog Post on Validation Objects and Properties with Validator:

When validating an object, the
following process is applied in
Validator.ValidateObject:

1. Validate property-level attributes
2. If any validators are invalid, abort validation returning the
   failure(s)
3. Validate the object-level attributes
4. If any validators are invalid, abort validation returning the
   failure(s)
5. If on the desktop framework and the object implements
   IValidatableObject, then call its
   Validate method and return any
   failure(s)

This indicates that what you are attempting to do won’t work out-of-the-box because the validation will abort at step #2.