[asp.net-mvc] ASP.NET MVC Html.ValidationSummary(true) does not display model errors

Maybe like that:

[HttpPost]
public ActionResult Register(Member member)
{
    try
    {
       if (!ModelState.IsValid)
       {
          ModelState.AddModelError("keyName", "Form is not valid");
          return View();
       }
       MembersManager.RegisterMember(member);
    }
    catch (Exception ex)
    {
       ModelState.AddModelError("keyName", ex.Message);
       return View(member);
    }
}

And in display add:

<div class="alert alert-danger">
  @Html.ValidationMessage("keyName")
</div>

OR

<div class="alert alert-danger">
  @Html.ValidationSummary(false)
</div>