Umbraco Forms validation example

FormsValidationExample.cs

    public class FormsValidation : ApplicationEventHandler
    {
        protected override void ApplicationStarted(UmbracoApplicationBase umbracoApplication, ApplicationContext applicationContext)
        {
            Umbraco.Forms.Web.Controllers.UmbracoFormsController.FormValidate += UmbracoFormsController_FormValidate;
        }

        void UmbracoFormsController_FormValidate(object sender, Umbraco.Forms.Mvc.FormValidationEventArgs e)
        {

            if (e.Form.Name == "Workshop Signup")
            {
                var s = sender as Controller;
                if (s != null)
                {
                    var emf = e.Form.AllFields.SingleOrDefault(f => f.Caption == "Email").Id.ToString();
                    var pwf = e.Form.AllFields.SingleOrDefault(f => f.Caption == "Password").Id.ToString();


                    var email = e.Context.Request[emf];
                    var password = e.Context.Request[pwf];

                    if (Profiles.Login(email, password))
                    {
                        //check if there is a spot left, just count subnodes



                        var help = new UmbracoHelper(UmbracoContext.Current);
                        var workshop = help.TypedContent(UmbracoContext.Current.PageId);
                        var spotLeft = workshop.Children.Count() < Convert.ToInt32(workshop.GetPropertyValue("maxAttendees"));

                        if (!spotLeft)
                        {
                            s.ModelState.AddModelError(pwf, "Sorry today's seats are gone, we'll release some more soon.");


                        }

                    }
                    else
                    {
                        s.ModelState.AddModelError(pwf, "UmbracoID could not find your credentials, make sure you have an account on umbraco.com with a confirmed codegarden 2015 ticket.");

                    }

                }
            }
        }
    }