How do I custom validate collections withing MVC5 - validation

Question

I am building an MVC5 application and I have the following viewmodels:
public class UserPartyViewModel
{
public UserPartyViewModel()
{
Entitlements = new Collection<AssignedClaims>();
}
public Guid PartyID { get; set; }
public string PartyName { get; set; }
public ICollection<AssignedClaim> AssignedClaims{ get; set; }
}
public class AssignedClaims
{
public AssignedClaims()
{
ClaimValues = new Collection<AssignedClaimValue>();
}
public string Name { get; set; }
public int Max { get; set; }
public int Min { get; set; }
public ICollection<AssignedClaimValue> ClaimValues { get; set; }
}
public class AssignedClaimValue
{
public Guid ClaimValueID { get; set; }
public string ClaimValue { get; set; }
public bool Assigned { get; set; }
}
Contained in the UserPartyViewModel will always be an assignedclaim with a name of "Security" and the assignedclaimvalue with a claimvalue of "User"
If the ClaimValue of user is Assigned then I need to validate the rest of the model. If it is not then no further validation should take place.
Within AssignedClaims there is a min and max, these are the minimum and maximum number of assignedclaimvalues that should be Assigned.
I have tried to use AttributeValidate cannot stop it validating the rest of the model.
I have also looked at the IValidatableObject interface but also can't work out how to control the validation of the child collections depending on the User claim.
What's the best way to achieve this?

Answer 1

Found a solution which appears to do what I want:
public class UserPartyViewModel : IValidatableObject
{
public UserPartyViewModel()
{
Entitlements = new Collection<AssignedClaims>();
}
public string AccessLevel { get; set; }
public Guid PartyID { get; set; }
public string PartyName { get; set; }
public ICollection<AssignedClaims> Entitlements { get; set; }
public IEnumerable<ValidationResult> Validate(ValidationContext validationContext)
{
var isUser = Entitlements.Any(c => c.Name == "Security" && c.ClaimValues.Any(v => v.Assigned == true && v.ClaimValue == "User"));
if (isUser)
{
int i = 0;
foreach (var result in Entitlements)
{
yield return result.Validate(i++);
}
}
else
{
yield return ValidationResult.Success;
}
}
}
public class AssignedClaims
{
public AssignedClaims()
{
ClaimValues = new Collection<AssignedClaimValue>();
}
public string Name { get; set; }
public string Description { get; set; }
public int Max { get; set; }
public int Min { get; set; }
public ICollection<AssignedClaimValue> ClaimValues { get; set; }
public ValidationResult Validate(int item)
{
int min = Min;
int max = (ClaimValues.Count() < Max) ? ClaimValues.Count() : Max;
int assignedCount = ClaimValues.Where(i => i.Assigned == true).Count();
if (!(min <= assignedCount && assignedCount <= max))
{
string errMessage = String.Format("{2} should have between {0} and {1} Security Claims checked.", min, max, Name);
return new ValidationResult(errMessage, new[] { string.Format("Entitlements[{0}]", item) });
}
else
{
return ValidationResult.Success;
}
}
}
The only issue I had was trying to get the error messages appearing in the correct place. In my view for assignedclaims I added:
#Html.ValidationMessageFor(model => model, "", new { #class = "text-danger" })
and passed the iteration through to the validate function on assignedclaim to ensure it was added to the correct member.