Dynamic Class where properties come from a list/dictionary

Question

I would like to create a dynamic class doing with the following:

I have a dictionary where the keys are integers and the values are strings.

Dictionary<int, string> PropertyNames =  new Dictionary<int, string>();
PropertyNames.Add(2, "PropertyName1");
PropertyNames.Add(3, "PropertyName2");
PropertyNames.Add(5, "PropertyName3");
PropertyNames.Add(7, "PropertyName4");
PropertyNames.Add(11,"PropertyName5");

I would like to pass this dictionary into a class constructor which builds Properties into the class instance. And suppose I would like to have both get and set functionality for each of these properties. e.g.:

MyDynamicClass Props = new MyDynamicClass( PropertyNames );
Console.WriteLine(Props.PropertyName1);
Console.WriteLine(Props.PropertyName2);
Console.WriteLine(Props.PropertyName3);
Props.PropertyName4 = 13;
Props.PropertyName5 = new byte[17];

I am having trouble understanding DLR.

See this article, I think this will help: http://stackoverflow.com/questions/2974008/adding-unknown-at-design-time-properties-to-an-expandoobject — Glenn Ferrie, Mar 12 '13 at 01:16
You're basically describing the `ExpandoObject`. Check it out: http://msdn.microsoft.com/en-us/library/system.dynamic.expandoobject.aspx — Sorax, Mar 12 '13 at 01:24
Oh okay, I think that is straightforward enough. I never knew about ExpandoObject. — Maelstrom Yamato, Mar 12 '13 at 01:36
Just out of curiousity, would anyone know why MSFT decided to name the class ExpandoObject instead of ExpandObject? It seems like a typo. — Maelstrom Yamato, Mar 12 '13 at 01:37
Just FYI, you are discarding almost all compile-time checks and sacrificing performance when you use such types as ExpandoObject or DynamicObject. — Anton Tykhyy, Mar 12 '13 at 03:05
@AntonTykhyy Thank you for letting me know about the performance penalty. This might be a deal breaker for me since I do have timing requirements. — Maelstrom Yamato, Mar 14 '13 at 13:53

score 1 · Answer 1 · answered Mar 12 '13 at 02:31

The DynamicObject class seems to be what you want. In fact the documentation shows how to do exactly what you asked. Reproduced here in a stripped down version for brevity:

public class DynamicDictionary : DynamicObject
{
    Dictionary<string, object> dictionary = new Dictionary<string, object>();

    public int Count
    {
        get { return dictionary.Count; }
    }

    public override bool TryGetMember(GetMemberBinder binder, out object result)
    {
        string name = binder.Name.ToLower();
        return dictionary.TryGetValue(name, out result);
    }

    public override bool TrySetMember(SetMemberBinder binder, object value)
    {
        dictionary[binder.Name.ToLower()] = value;
        return true;
    }
}

Dynamic Class where properties come from a list/dictionary

1 Answers1