Accessing custom properties and their values in an object using reflection in C#

Question

Consider we have model like:

class Person{
    public string Name{get; set;}
    public List<Contact> ContactInfo{get; set;}
 }

and Contact is like:

class Contact{
   public string Landline{get; set;}
   public string Mobile{get; set;}
}

I want to access ContactInfo(List<Contact>) and hence fetch values of Landline and Mobile using reflection in C#.

So those classes are not defined in your assembly, they're external? How are you getting an instance of a `Person` if the class is `internal`? — Furkan Kambay, Dec 14 '18 at 14:24
What have you tried doing? Have you read up on the [Reflection Docs](https://learn.microsoft.com/en-us/dotnet/csharp/programming-guide/concepts/reflection)? — derekmckinnon, Dec 14 '18 at 14:24
@UmangSrivastava Then you have access to those properties; why reflection? — Furkan Kambay, Dec 14 '18 at 14:31
@pteberf I'll be getting an object and then I have to work my way backward from there to fetch values of properties. — maverick6912, Dec 14 '18 at 14:31
@Furkan because at runtime i don't know the type I'm getting all i'm getting is an object in my method parameters. In short it has to be a general solution for any class defined in assembly. — maverick6912, Dec 14 '18 at 14:34
Did you take a look at this answer? https://stackoverflow.com/a/1197004/4187549 — Furkan Kambay, Dec 14 '18 at 14:36
how many classes are there like this? can you make the method parameters(out?) typed? can you make use of generics? — Furkan Kambay, Dec 14 '18 at 14:38
@FurkanKambay there are a hell lot of classes. I cant make them "out". Yes we can use generics. — maverick6912, Dec 14 '18 at 14:39
I think you need to describe the problem a little better. This will take more time to figure out in comments. — Furkan Kambay, Dec 14 '18 at 14:42
When I said "(out?)", I meant, those parameters are `out` parameters right? — Furkan Kambay, Dec 14 '18 at 14:43
public override void DoValidate(object objectToValidate, object currentTarget, string key, ValidationResults validationResults) — maverick6912, Dec 14 '18 at 14:48
And how exactly are you planning to validate all your entities using reflection? — Seva, Dec 14 '18 at 14:54
@pteberf I'm checking the entities values against blacklisted characters. I just want to know how can I traverse the ContactList and fetch values. — maverick6912, Dec 14 '18 at 14:57
@UmangSrivastava IMO - that should be your question. And, again, imo, usage of reflection is a bad answer to this question. — Seva, Dec 14 '18 at 17:35
Are the different classes related? Can you use an `interface` to specify the commonality and then use that? `public override void DoValidate(IHasContactInfo objectToValidate, object currentTarget, string key, ValidationResults validationResults)` — NetMage, Dec 14 '18 at 21:03

score 1 · Answer 1 · answered Dec 14 '18 at 14:40

using System;
using System.Collections.Generic;
using System.Linq;
using System.Reflection;

namespace ConsoleApp1
{
    class Program
    {
        class Contact
        {
            public string Landline { get; set; }
            public string Mobile { get; set; }
        }

        class Person
        {
            public string Name { get; set; }
            public List<Contact> ContactInfo { get; set; }
        }

        static void Main(string[] args)
        {
            Person person = new Person();
            person.ContactInfo = new List<Contact>();
            person.ContactInfo.Add(new Contact { Landline = "123456", Mobile = "7654332"});

            PropertyInfo contactInfoPropertyInfo = person.GetType().GetProperty(nameof(Person.ContactInfo));
            List<Contact> contactInfoValue = contactInfoPropertyInfo.GetValue(person, null) as List<Contact>;
            Contact firstContact = contactInfoValue?.First();
            string landline = firstContact?.GetType().GetProperty(nameof(Contact.Landline))?.GetValue(firstContact, null) as string;
            string mobile = firstContact?.GetType().GetProperty(nameof(Contact.Mobile))?.GetValue(firstContact, null) as string;

            Console.WriteLine(landline);
            Console.WriteLine(mobile);
        }
    }
}

score 1 · Accepted Answer · answered Dec 14 '18 at 14:51

1

 private static string GetReflectedLandlineValue(object person)
 {
      IEnumerable<object> contactList = (IEnumerable<object>)person.GetType().GetProperty("ContactInfo")?.GetValue(person);
      return (string) contactList.First().GetType().GetProperty("Landline")?.GetValue(contactList.First());
 }

answered Dec 14 '18 at 14:51

MrVoid

709
5
19

notice this is just to reflect the landline property from the first item of the collection , if you want to do this for each item of the collection you need to extract the part of the logic out. – MrVoid Dec 17 '18 at 14:36

Accessing custom properties and their values in an object using reflection in C#

2 Answers2