asp.net MVC data validation membership using common errors

In doing the registration interface, there are two errors, let me tangle to die, fortunately, finally resolved, can only blame themselves on the MVC membership know not deeply, especially about the configuration of web.config.

Problem One: Membership.isvalid returns to False

This question at first made me very silent, because before also has done the registration interface, but does not appear this kind of question, the code is as follows:

[HttpPost] public actionresult Register (Registermodel model) {if (modelstate.isvalid)
                {///attempt to register the user MembershipCreateStatus Createstatus; Membership.CreateUser (model. UserName, model. Password, model.
                Email, NULL, NULL, TRUE, NULL, out createstatus); if (Createstatus = = membershipcreatestatus.success) {Formsauthentication.setauth Cookie (model.
                    UserName, False/* createPersistentCookie *);
                Return redirecttoaction ("LogOn", "account"); else {modelstate.addmodelerror ("test"), Errorcodetostring (Createstat
                    US));
                Return redirecttoaction ("Index", "Home");
    
            }//If We got this far, something failed, redisplay form
        return View (model); }