mvc3 ，局部视图不刷新的问题

Question

@if (Request.IsAuthenticated)
{
  <span>  welcome  @Context.User.Identity.Name     </span>
    @Html.ActionLink("Log Off", "LogOff")
}
else
{
    @Html.ActionLink("Log On","LogOn")
}
上面是局部视图，当我登录以后，这部分不刷新  
     [HttpPost]
        public ActionResult LogOn(wu_Member m)
        {
            if (ModelState.IsValid)
            {
                try
                {
                Accout.SignIn(m.MemName, true);
                }
                catch (ArgumentException ex)
                {
                    ModelState.AddModelError("userName", ex.Message); 
                     
                }
            
                return View();  
            }            return View();
        }