ASP.NET MVC Filtering results in a list/grid

Question

For some reason I\'m stuck on this. I need to filter results from a View based on a DropDownList in the same view. The basic idea is this: I have a list of providers that be

Answer 1

EDIT: If you want to do this with jQuery and AJAX (which will provide a better user experience because only the subdivisions list will refresh), see this tutorial.

If I understand correctly, you basically want to do a WebForms-style postback.

Let's say you have a control with countries and country subdivisions (e.g. states, provinces, etc). When the country changes, you want the appropriate subdivisions to display.

So this would be view:

<% using (Html.BeginForm()) { %>
    <%=Html.DropDownList("Address.CountryId", new SelectList(Country.GetAll(), "Id", "Name"), new { onchange = "this.form.submit();" })%>
    <%=Html.DropDownList("Address.CountrySubdivisionId", new SelectList(CountrySubDivision.GetByCountryId(Model.CountryId), "Id", "Name"))%>
    
<%} %>

This is the key to getting the dependent list to filter:

new { onchange = "this.form.submit();" }

And in the controller, you'd have something like this:

    [AcceptVerbs(HttpVerbs.Post)]
    public ViewResult Index(string btnSubmit)
    {
        if (btnSubmit == null)
        {
            // return the view displayed upon GET
        }
        else
        {
            // process the submitted data
        }
    }

In the above code, if the form submission was triggered by changing the value in a dropdown, btnSubmit will be null. Thus, the action you are POSTing to can tell whether or not the user meant to finalize her changes.