Why can't I index into an ExpandoObject?

Question

Something caught me by surprise when looking into C# dynamics today (I\'ve never used them much, but lately I\'ve been experimenting with the Nancy web framework). I found t

Answer 1

Use this factory class to create ExpandoObjects! Then use HasProperty("prop name") or GetValue("prop name")

void Main()
{
    dynamic _obj = ExpandoObjectFactory.Create();
    if (_obj.HasProperty("Foo") == false)
    {
        _obj.Foo = "Foo";
    }
    Console.WriteLine(_obj); // Foo;
    object bar = _obj.GetValue("Bar");
    Console.WriteLine(bar); // null
}

public static class ExpandoObjectFactory
{
    public static ExpandoObject Create()
    {
        dynamic expandoObject = new ExpandoObject();
        expandoObject.HasProperty = new Func((string name) => ((IDictionary)expandoObject).ContainsKey(name));
        expandoObject.GetValue = new Func(delegate (string name)
        {
            ((IDictionary)expandoObject).TryGetValue(name, out object value);
            return value;
        });
        return expandoObject;
    }
}