How to access a dynamic object's property dynamically (by variable)?

I have a class named Configurationwhich inherits from DynamicObject. It it a Dictionary<string, object>. In the constructor, it reads a text file and loads all the values from it splitted by =, so you can create dynamic configuration objects like this:

dynamic configuration = new Configuration("some_file.ini");

Here is my full class:

public sealed class Configuration : DynamicObject
{
    private string Path { get; set; }
    private Dictionary<string, object> Dictionary { get; set; }

    public Configuration(string fileName)
    {
        this.Path = fileName;
        this.Dictionary = new Dictionary<string, object>();

        this.Populate();
    }

    ~Configuration()
    {
        if (this.Dictionary != null)
        {
            this.Dictionary.Clear();
        }
    }

    private void Populate()
    {
        using (StreamReader reader = new StreamReader(this.Path))
        {
            string line;
            string currentSection = string.Empty;

            while ((line = reader.ReadLine()) != null)
            {
                if (string.IsNullOrWhiteSpace(line))
                {
                    continue;
                }

                if (line.StartsWith("[") && line.EndsWith("]"))
                {
                    currentSection = line.Trim('[', ']');
                }
                else if (line.Contains("="))
                {
                    this.Dictionary.Add(string.Format("{0}{1}{2}",
                        currentSection,
                        (currentSection != string.Empty) ? "_" : string.Empty,
                        line.Split('=')[0].Trim()),
                        ParseValue(line.Split('=')[1].Trim().Split(';')[0]));
                }
            }
        }
    }

    private object ParseValue(string value)
    {
        if (string.IsNullOrWhiteSpace(value))
            return string.Empty;

        if (value.StartsWith("\"") && value.EndsWith("\""))
            return value.Substring(1, value.Length - 1);

        if (IsNumeric(value))
            return Convert.ToInt32(value);

        // TODO: FIXME Floating values (not to be confuse with IPAddress).
        //if (IsFloating(value))
        //    return Convert.ToDouble(value);

        if (string.Compare(value, "true", StringComparison.OrdinalIgnoreCase) == 0)
            return true;

        if (string.Compare(value, "false", StringComparison.OrdinalIgnoreCase) == 0)
            return false;

        return value;
    }

    public override bool TryGetMember(GetMemberBinder binder, out object result)
    {
        if (this.Dictionary.ContainsKey(binder.Name))
        {
            if (this.Dictionary[binder.Name] == null)
            {
                result = null;
            }
            else
            {
                result = this.Dictionary[binder.Name];
            }

            return true;
        }

        throw new ConfigurationException(binder.Name);
    }

    public override string ToString()
    {
        string result = this.Path + " [ ";

        int processed = 0;

        foreach (KeyValuePair<string, object> value in this.Dictionary)
        {
            result += value.Key;
            processed++;

            if (processed < this.Dictionary.Count)
            {
                result += ", ";
            }
        }

        result += " ]";

        return result;
    }

    private static bool IsNumeric(string value)
    {
        foreach (char c in value)
            if (!char.IsDigit(c))
                return false;

        return true;
    }
    private static bool IsFloating(string value)
    {
        foreach (char c in value)
            if (!char.IsDigit(c) && c != '.')
                return false;

        return true;
    }

    private class NullObject { }
}

Everything is working flawlessly. I've overriden TryGetMember and I'm returning the object based on the GetMemberBinder Name property. However, I'm facing a problem.

When I execute the following code:

string s = "some_config_key";

string d = configuration.s;

It retrieves the value of the key s rather than some_config_key, meaning that it doesn't evalute the value of the variable s. Is there a workaround for this?

Thanks.