如何获取包含局部视图的主视图？

Question

表单提交后我得到部分视图（它不包含主视图）。如何获取包含局部视图的主视图？

视图：

@using (Ajax.BeginForm("Index", "Home", new AjaxOptions { HttpMethod = "POST", UpdateTargetId = "result", OnBegin = "onBegin()", OnComplete = "onComplate()" }))
{
<div id="result"></div>
...

控制器：

        public ActionResult Index()
        {
            return View(model);
        }

[HttpPost]
public PartialViewResult Index(mdl model)
{
...
return PartialView("_part", model);
}