mvc 5 custom validation for variables inside of model object - asp.net-mvc-5

Question

I have searched for this question in multiple places and was unable to find exactly what I am looking for. Let's say I have this MVC Model Structure:
public class Person {
[Required]
public string Name { get; set; }
public int Age { get; set; }
}
public class Workers {
[AgeRequired]
public Person Pilots { get; set; }
public Person Chefs { get; set; }
}
and here would be my cshtml code:
#Model Workers
<div>
<label asp-for="Pilots.Name"></label>
<input asp-for="Pilots.Name"></input>
<span asp-validation-for="Pilots.Name"></span>
</div>
<div>
<label asp-for="Pilots.Age"></label>
<input asp-for="Pilots.Age"></input>
<span asp-validation-for="Pilots.Age"></span>
</div>
<div>
<label asp-for="Chefs.Name"></label>
<input asp-for="Chefs.Name"></input>
<span asp-validation-for="Chefs.Name"></span>
</div>
<div>
<label asp-for="Chefs.Age"></label>
<input asp-for="Chefs.Age"></input>
<span asp-validation-for="Chefs.Age"></span>
</div>
Person is a generic Model class that holds information about Pilots or Chefs. What I want is for my AgeRequired Custom Validation Attribute to make Age required only when referring to Pilots, not Chefs. Would that be possible?
I have it working on the backend side, after the form has been submitted, however I would like this to be on the front end as well. Here is my code for my Attribute:
[AttributeUsage(AttributeTargets.Property, AllowMultiple = false, Inherited = false)]
public class AgeRequiredAttribute: ValidationAttribute, IClientModelValidator
{
public override bool IsValid(object value)
{
Workers workers = value as Workers;
return workers.Age > 0;
}
public IEnumerable<ModelClientValidationRule> GetClientValidationRules(ClientModelValidationContext context)
{
yield return new ModelClientValidationRule("agerequired", "{0} is a required field.");
}
}
}
and here is my javascript code for the front end validation:
/// <reference path="jquery.validate.js" />
/// <reference path="jquery.validate.unobtrusive.js" />
$.validator.addMethod("agerequired",
function (value, element, parameters) {
return value > 0;
});
$.validator.unobtrusive.adapters.add("agerequired", [], function (options) {
options.rules.agerequired= {};
options.messages["agerequired"] = options.message;
});
ClientValidationEnabled and UnobstrusiveJavaScriptEnabled are both set to true.
This custom attribute will work when I have it on the Age field itself, but that makes it required for both Pilots and Chefs. I only want it required for Pilots.
Thank you in advance for your help!

Answer 1

I was actually able to create a work around for those who are interested.
If you put in the data-val-[attribute] that would get generated by MVC directly into your input tag or select tag, followed by the error message you want to throw, it will do the front end validation, and still do the back end validation as MVC will notice that the complex object has information in it. It's not ideal, but probably what I will have to do.
For example:
#Model Workers
<div>
<label asp-for="Pilots.Name"></label>
<input asp-for="Pilots.Name"></input>
<span asp-validation-for="Pilots.Name"></span>
</div>
<div>
<label asp-for="Pilots.Age"></label>
<input asp-for="Pilots.Age" data-val-agerequired="Age is Required for Pilots."></input>
<span asp-validation-for="Pilots.Age"></span>
</div>
<div>
<label asp-for="Chefs.Name"></label>
<input asp-for="Chefs.Name"></input>
<span asp-validation-for="Chefs.Name"></span>
</div>
<div>
<label asp-for="Chefs.Age"></label>
<input asp-for="Chefs.Age"></input>
<span asp-validation-for="Chefs.Age"></span>
</div>
Will work. It's not ideal, but it allows us to keep the MVC Back End validation in the same spot.

Answer 2

Another option is to have person age as optional in a base class.
public int? Age { get; set; }
Inherit Chef and Pilot from Person. In pilot, make the age value non-optional - you'll probably want to make sure they have a minimal age too using Data Annotations
public new int Age { get; set; }
The model is now a list of Persons. The client should be able to work out which is optional and which is not