EF Core2.0 dbvalidation errors not displaying all errors - asp.net-core

Question

I've Created an EF core 2.0 application and trying to validate the model on Savechanges but its only returning the first validation error.
Here are my Dbcontext and controller
public partial class ProductWarehouseContext : DbContext
{ public List<string> ErrorList=new List<string>();
public ProductWarehouseContext(DbContextOptions<ProductWarehouseContext> options)
: base(options)
{
}
public virtual DbSet<Customer> Customer { get; set; }
public virtual DbSet<Order> Order { get; set; }
public virtual DbSet<OrderItem> OrderItem { get; set; }
public virtual DbSet<Product> Product { get; set; }
public virtual DbSet<Supplier> Supplier { get; set; }
public override int SaveChanges()
{
var entities = from e in ChangeTracker.Entries()
where e.State == EntityState.Added
|| e.State == EntityState.Modified
select e.Entity;
foreach (var entity in entities)
{
var validationContext = new ValidationContext(entity);
Validator.ValidateObject(
entity,
validationContext,
validateAllProperties: true);
}
return base.SaveChanges();}
}
Controller
[HttpPost]
public IActionResult Save([FromBody]CustomerViewModel customer)
{
using (var cont = _context.Database.BeginTransaction())
{
try
{
var cust = new Customer()
{
FirstName = customer.FirstName,
LastName = customer.LastName,
City = customer.City,
Country = customer.Country,
Phone = customer.Phone,
IsSubscribedforAlerts = customer.IsSubscribedforAlerts
};
_context.Customer.Add(cust);
_context.SaveChanges();
cont.Commit();
}
catch (Exception e)
{
Errors.Add(e.Message);
cont.Rollback();
foreach (var err in Errors)
{
ModelState.AddModelError("errors", err);
}
return Ok(ModelState);
}
}
return Ok();
}
Class
public partial class Customer
{
public Customer()
{
Order = new HashSet<Order>();
}
public int Id { get; set; }
[Required(ErrorMessage = "FirstName is required to save a new customer")]
public string FirstName { get; set; }
[Required(ErrorMessage = "LastName is required to save a new customer")]
public string LastName { get; set; }
public string City { get; set; }
public string Country { get; set; }
[Required(ErrorMessage = "PhoneNumber is required to save a new customer")]
public string Phone { get; set; }
public bool? IsSubscribedforAlerts { get; set; }
public ICollection<Order> Order { get; set; }
}
and error is only returnig ""firstname" is required and if I pass the firstname in request object then its returning "lastname" is required.
What should I do to return all the errors how we do it in EF6 using DbEntityValidationException ?

Answer 1

That's because ValidateObject() throws upon first encountering an error. Try using TryValidateObject() instead, and pass it a List<ValidationResult> that accumulate all errors.
Something like:
public class EntityValidationException : Exception
{
public EntityValidationException(IEnumerable<ValidationException> exceptions)
{
this.ValidationErrors = exceptions;
}
public IEnumerable<ValidationException> ValidationErrors { get; }
}
Then in your SaveChanges():
foreach (var entity in entities)
{
var validationContext = new ValidationContext(entity);
var validationResults = new List<ValidationResult>();
Validator.TryValidateObject(entity, validationContext, validationResults);
if (validationResults.Any())
throw new EntityValidationException(validationResults.Select(x => new ValidationException(x, null, null)));
}
Then in your controller/action, you can explicitly handle EntityValidationException:
catch (EntityValidationException validationException)
{
foreach (var err in validationException.ValidationErrors)
{
var validationResult = err.ValidationResult;
ModelState.AddModelError(validationResult.MemberNames.First(), validationResult.ErrorMessage);
}
}