How to reference invalid property in object?

Question

Sorry, If this question seems too broad, but I'm a little unsure how I should do this task.

I have some objects:

public class A
{
    public B b {get;set;}
    public C[] cList {get;set;}
}

public class B
{
    public string val1 {get;set;}
}

public class C
{
    public string val2 {get;set;}
}

And a set of validators:

public class AValidator : IValidator<A>
{
    IEnumerable<ValidationError> Validate(A obj){...}
}

public class BValidator : IValidator<B>
{
    IEnumerable<ValidationError> Validate(B obj){...}
}

public class CValidator : IValidator<C>
{
    IEnumerable<ValidationError> Validate(C obj){...}
}

Error looks like this:

public class ValidationError
{
    public int Code {get;set;}
    public string Message {get;set;}
}

I perform validation like this:

_validator.Validate(new A()).ThrowIfInvalid();

But here is the problem, how to reference invalid property and Serialize/Deserialize this reference to use it on client?

For example, if new A().c[2].val2 is invalid, I should be able to obtain this path on server and use it on client for my view (obtain PropertyInfo, and object).

Is there some extensions/libraries in C# which provide serializable references for properties? For example, like XPath in XML.

Answer 1

Extend class ValidationError with PropertyPath property and prepend it on each parent validator

public class AValidator : IValidator<A>
{
    IEnumerable<ValidationError> Validate(A obj)
    {
        if(obj.b == null)
            yield return new ValidationError {Message = "b is null", PropertyPath = "a.b"};
        else
        { 
            var bresults = new BValidator().Validate(obj.b);
            foreach(var result in bresults)
            {
                result.PropertyPath = "a.b." + result.PropertyPath;
                yield return result;
            }
        }
...
            var cresults = new BValidator().Validate(obj.c[i]);
            foreach(var result in cresults)
            {
                result.PropertyPath = "a.c[i]." + result.PropertyPath;
                yield return result;
            }
    }        
}