Dynamic member resolution chaining

gistfile1.cs

namespace DynamicMemberChaining
{
    using System;
    using System.Dynamic;

    using Xunit;

    public interface ITextResource
    {
        string this[string key] { get; }
    }

    public class DefaultTextResource : ITextResource
    {
        public string this[string key]
        {
            get { return "Returned from resource, for key: " + key; }
        }
    }

    public class TextResourceFinder : DynamicObject
    {
        private readonly ITextResource textResource;

        public TextResourceFinder(ITextResource textResource)
        {
            this.textResource = textResource;
        }

        public override bool TryGetMember(GetMemberBinder binder, out object result)
        {
            result = new MemberChainer(binder.Name, this.textResource);
            return true;
        }

        private class MemberChainer : DynamicObject
        {
            private string memberName;
            private readonly ITextResource textResource;

            public MemberChainer(string memberName, ITextResource resource)
            {
                this.memberName = memberName;
                this.textResource = resource;
            }

            public override bool TryGetMember(GetMemberBinder binder, out object result)
            {
                this.memberName =
                    string.Concat(this.memberName, ".", binder.Name);

                result = this;

                return true;
            }

            public override bool TryConvert(ConvertBinder binder, out object result)
            {
                if (binder.ReturnType == typeof (string))
                {
                    result = this.textResource[this.memberName];
                    return true;
                }

                throw new InvalidOperationException("Cannot cast dynamic member access to anything else than a string.");
            }
        }
    }

    public class Fixture
    {
        [Fact]
        public void Should_FactMethodName()
        {
            // Given
            var textResource = new DefaultTextResource();
            dynamic finder = new TextResourceFinder(textResource);

            // When
            var result = finder.foo.bar.other;

            // Then
            Assert.Equal("Returned from resource, for key: foo.bar.other", (string)result);
        }
    }
}