LogOnHandler.cs

using ALS.Validation.Ajax;
using FubuMVC.Core.Ajax;
using FubuMVC.Core.Security;
using HelloWorld.Handlers.Home;
using HelloWorld.Services;

namespace HelloWorld.Handlers.Account
{
    // ...

    public class LogOnModel : IHaveValidationPreview
    {
        public string UserName { get; set; }
        public string Password { get; set; }
        public bool RememberMe { get; set; }
        // public string Error { get; set; }
    }
}