using System;

using System.Reflection;

using System.Text.RegularExpressions;

using System.Linq;

using System.Collections.Generic;

public class Program

{

    public static void Main(string[] s)

    {

        var a1 =  new A(new B(new C[] { new C(1), new C(2), new C(3) }));

        Console.WriteLine(GetFieldValueByPath(a1, "b.cItems[2].target"));

​

        var a2 =  new A(new B(new C[] { } ));

        Console.WriteLine(GetFieldValueByPath(a2, "b.cItems[2].target"));

​

        var a3 =  new A(new B(null));

        Console.WriteLine(GetFieldValueByPath(a3, "b.cItems[2].target"));

    }

    public static object GetFieldValueByPath(object obj, string fieldPath)

    {

        var flags = 

            BindingFlags.Static | BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic;

        var splitted = fieldPath.Split('.');

​

        var current = splitted[0];

        int? index = null;

​

        // Support getting a certain index in an array field

        var match = Regex.Match(current, @"\[([0-9]+)\]");

        if (match.Groups.Count > 1)

        {

            current = fieldPath.Substring(0, match.Groups[0].Index);

            index = int.Parse(match.Groups[1].Value);

        }

​

        object value;

        try

        {

            value = obj.GetType().GetField(current, flags).GetValue(obj);

        }

        catch (NullReferenceException ex)

        {

            throw new Exception(string.Format("Wrong path provided: field '{0}' does not exist on '{1}'", current, obj));

        }

​

        if (value == null)

        {

            return null;

        }

​

        if (splitted.Length == 1)

        {

            return value;

        }

​

        if (index != null)

        {

            var asIList = (IList<object>)value;

            if (asIList != null && asIList.Count >= index.Value)

            {

                value = asIList[index.Value];

            }

            else

            {

                return null;

            }

        }

​

        return GetFieldValueByPath(value, string.Join(".", splitted.Skip(1)));

    }

}

​

public class A

{

   private B b;

   public A(B b) { this.b = b; }

}

​

public class B

{

   private C[] cItems;

   public B(C[] cItems) { this.cItems = cItems; }

}

​

public class C

{

   private int target; // <-- get this value

   public C(int val) { this.target = val; }

}