<div class="<$Model.ClassName$> gadget" id="<$Model.Id$>">
  <!-- THIS IS AN EMPTY TEMPLATE, BECAUSE ASPX IS RENDERED -->
  <$Model.GadgetHtml$>
</div>

public class SubscriptionModuleController : ModuleController
{
    public SubscriptionModuleController(IGadgetViewProvider gadgetViewProvider)
        : base(gadgetViewProvider)
    {
    }

    public override ActionResult Index()
    {
        var viewHelper = new WebFormsViewHelper(this.ControllerContext);
        var viewModel = (SubscriptionModel)this.gadgetViewProvider.GetGadgetModel();

        viewModel.GadgetHtml = viewHelper.RenderView(this.View(viewHelper.GetWebFormsView(viewModel)));

        return this.View(viewModel);
    }
}

<div class=" gadget" id="id_Mi7ljRe">
  <!-- THIS IS AN EMPTY TEMPLATE, BECAUSE ASPX IS RENDERED -->   
<form method="post" action="./" onsubmit="javascript:return WebForm_OnSubmit();" id="form">
<div class="aspNetHidden">
<input type="hidden" name="__LASTFOCUS" id="__LASTFOCUS" value="">
<input type="hidden" name="__EVENTTARGET" id="__EVENTTARGET" value="">
<input type="hidden" name="__EVENTARGUMENT" id="__EVENTARGUMENT" value="">
<input type="hidden" name="__VIEWSTATE" id="__VIEWSTATE" value="/wEPDwUKMTQwMTYyMzA1OGRk">
</div>
<script type="text/javascript">
//<![CDATA[
var theForm = document.forms['form'];
if (!theForm) {
    theForm = document.form;
}
function __doPostBack(eventTarget, eventArgument) {
    if (!theForm.onsubmit || (theForm.onsubmit() != false)) {
        theForm.__EVENTTARGET.value = eventTarget;
        theForm.__EVENTARGUMENT.value = eventArgument;
        theForm.submit();
    }
}
//]]>
</script>
<!-- пропущено -->
</div>