Using DynamicObject (IDynamicMetaObjectProvider) as a component of a static type leads to infinite loop

Question

I\'m trying to create a dynamic object that can be used as a component of a static object. Here is a contrived example of what I\'m trying to accomplish.

Here is the dy

Answer 1

I think the problem is that the Expression parameter passed to GetMetaObject represents the target of the dynamic invocation (i.e. the current object). You are passing the outer object to the call on component.GetMetaObject, so the returned meta object is trying to resolve the call to AMethod on the outer object instead of itself, hence the infinite loop.

You can create your own meta object which delegates to the inner component when binding member invocations:

public class AStaticComponent : VendorLibraryClass, IDynamicMetaObjectProvider
{
    IDynamicMetaObjectProvider component = new DynamicComponent();

    public DynamicMetaObject GetMetaObject(Expression parameter)
    {
        return new DelegatingMetaObject(component, parameter, BindingRestrictions.GetTypeRestriction(parameter, this.GetType()), this);
    }

    private class DelegatingMetaObject : DynamicMetaObject
    {
        private readonly IDynamicMetaObjectProvider innerProvider;

        public DelegatingMetaObject(IDynamicMetaObjectProvider innerProvider, Expression expr, BindingRestrictions restrictions)
            : base(expr, restrictions)
        {
            this.innerProvider = innerProvider;
        }

        public DelegatingMetaObject(IDynamicMetaObjectProvider innerProvider, Expression expr, BindingRestrictions restrictions, object value)
            : base(expr, restrictions, value)
        {
            this.innerProvider = innerProvider;
        }

        public override DynamicMetaObject BindInvokeMember(InvokeMemberBinder binder, DynamicMetaObject[] args)
        {
            var innerMetaObject = innerProvider.GetMetaObject(Expression.Constant(innerProvider));
            return innerMetaObject.BindInvokeMember(binder, args);
        }
    }
}