Custom DropDownFor loading Entity according to value
<p>I am working in an ASP.NET MVC project and I have a custom implementation of a DropDown list in my form.
I am selecting an account, and according to that account I want to be able to select the contacts made under the account. ( The Contacts model has an Accountid )</p>

<p>Here is my code below</p>

<pre><code> public static MvcHtmlString AccountContactsDropdownFor&lt;TModel, TEnum&gt;(this HtmlHelper&lt;TModel&gt; htmlHelper, Expression&lt;Func&lt;TModel, TEnum&gt;&gt; expression, Guid parentId, object htmlAttributes = null)
    {
        QueryRequestHelper&lt;AccountContacts, FMRequestDispatcher&gt; request = new QueryRequestHelper&lt;AccountContacts, FMRequestDispatcher&gt;();
        EntityReference reference = new EntityReference() { EntityName = "Account", Id = parentId };
        int count = 0;
        IEnumerable query = request.Query(string.Empty, string.Empty, 0, 100, out count, reference);

        List&lt;SelectListItem&gt; items = new List&lt;SelectListItem&gt;();
        foreach (Contact contacts in query)
        {
            SelectListItem li = new SelectListItem();
            li.Value = contacts.Id.ToString();
            li.Text = contacts.FirstName[0] + ". " + contacts.LastName;
            items.Add(li);
        }

        return SelectExtensions.DropDownListFor(htmlHelper, expression, items, htmlAttributes);
    }
</code></pre>

<p>And here is the code of it my form </p>

<pre><code>                &lt;li&gt;
                    @Html.Label(Localization_Financial.Account) &lt;br&gt;
                    @Html.AccountNameDropdownFor( m =&gt; m.AccountId)
                &lt;/li&gt;
                &lt;li&gt;
                    @Html.Label(Localization_Financial.Contact) &lt;br&gt;
                    @Html.AccountContactsDropdownFor(m =&gt; m.ContactId, Model.AccountId)
                &lt;/li&gt;
</code></pre>

<p>So whenever I am selecting an account in the dropdownfor above I want my application to sort of reload or do something so it updates the select box with the contacts which belong to my account.</p>

<p>Is there an effective way to do so?</p>