The problem is: when I put 2 controls of the same type on a page I need to specify different prefixes for binding. In this case the validation rules generated right after the form are incorrect. So how to get client validation work for the case?:

the page contains:

<%
    Html.RenderPartial(ViewLocations.Shared.PhoneEditPartial, new PhoneViewModel { Phone = person.PhonePhone, Prefix = "PhonePhone" });
    Html.RenderPartial(ViewLocations.Shared.PhoneEditPartial, new PhoneViewModel { Phone = person.FaxPhone, Prefix = "FaxPhone" });
%>

the control ViewUserControl<PhoneViewModel>:

<%= Html.TextBox(Model.GetPrefixed("CountryCode"), Model.Phone.CountryCode) %>
<%= Html.ValidationMessage("Phone.CountryCode", new { id = Model.GetPrefixed("CountryCode"), name = Model.GetPrefixed("CountryCode") })%>

where Model.GetPrefixed("CountryCode") just returns "FaxPhone.CountryCode" or "PhonePhone.CountryCode" depending on prefix

And here is the validation rules generated after the form. They are duplicated for the field name "Phone.CountryCode". While the desired result is 2 rules (required, number) for each of the FieldNames "FaxPhone.CountryCode", "PhonePhone.CountryCode"

The question is somewhat duplicate of http://stackoverflow.com/questions/2675606/asp-net-mvc2-clientside-validation-and-duplicate-ids-problem but the advise to manually generate ids doesn't helps.