Fun with proxies

ValidationListenerExtensions.cs

using Castle.DynamicProxy;

namespace MyCompany.Infrastructure.Validation
{
    public static class ValidationListenerExtensions
    {
        public static bool ListenAll(
            this IValidationListener listener,
            params IValidator[] validators)
        {
            var interceptor = new ErrorCatcherInterceptor();
            var proxy = new ProxyGenerator()
                .CreateInterfaceProxyWithTargetInterface(listener, interceptor);
            var success = true;

            foreach (var v in validators)
            {
                success &= v.Validate(proxy);
                if (interceptor.ErrorOccurred)
                    return false;
            }

            return success;
        }

        class ErrorCatcherInterceptor : IInterceptor
        {
            public bool ErrorOccurred { get; private set; }

            public void Intercept(IInvocation invocation)
            {
                invocation.Proceed();
                if (invocation.Method.Name == "OnError")
                    ErrorOccurred = true;
            }
        }
    }
}