<script type="text/javascript">
    $(function () {
        $('#theLink').click(function () {
            $.ajax({
                url: $(this).attr('href'),
                type: "GET",
                success: function (response) {
                    $('#mainContent').html(response);
                }
            });
return false;
        });
    });
</script>

@{
    Layout = Request.IsAjaxRequest() ? null : "~/Views/Shared/_Layout.cshtml";
}

在 controller:

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