title: How to fix Child actions are not allowed to perform redirect actions, other answers does not fix
body: <p>ASP.NET MVC2 view:</p>
  
  <pre><code>&lt;%@ Page Language="C#" MasterPageFile="~/Views/Shared/Site.Master" Inherits="System.Web.Mvc.ViewPage&lt;MvcMusicStore.ViewModels.PaymentViewModel&gt;" %&gt;
  
  &lt;asp:Content ID="Content2" ContentPlaceHolderID="MainContent" runat="server"&gt;
  
      ...
      &lt;form action="&lt;%= Html.Action("PaymentByBankTransfer", "Checkout") %&gt;" &gt;
      &lt;input type="submit" value="Payment by bank transfer" /&gt;
      &lt;/form&gt;
  </code></pre>
  
  <p>CheckoutController:</p>
  
  <pre><code>    public ActionResult PaymentByBankTransfer()
      {
          var order = Session["Order"] as Order;
          ExecCommand(@"update dok set confirmed=true where order={0}", order.OrderId);
          return CheckoutCompleteOK();
  
          var cart = ShoppingCart.GetCart(HttpContext);
          cart.EmptyCart();
          // https://stackoverflow.com/questions/1538523/how-to-get-an-asp-net-mvc-ajax-response-to-redirect-to-new-page-instead-of-inser?lq=1
          return JavaScript("window.location = '/Checkout/CompleteOK'");
      }
  
      // common method called from other controller methods also
      public ActionResult CheckoutCompleteOK()
      {
          var cart = ShoppingCart.GetCart(HttpContext);
          cart.EmptyCart();
          // prevent duplicate submit if user presses F5
          return RedirectToAction("Complete");
      }
  
     public ActionResult Complete()
      {
          var order = Session["Order"] as Order;
          SendConfirmation(order);
          return View("PaymentComplete", order);
       }
  </code></pre>
  
  <p>pressing form submit button causes exception</p>
  
  <pre><code>Child actions are not allowed to perform redirect actions
  </code></pre>
  
  <p>As code shows most upvoted answer from </p>
  
  <p><a href="https://stackoverflow.com/questions/1538523/how-to-get-an-asp-net-mvc-ajax-response-to-redirect-to-new-page-instead-of-inser?lq=1">How to get an ASP.NET MVC Ajax response to redirect to new page instead of inserting view into UpdateTargetId?</a></p>
  
  <p>is tried to fix it, but this causes other error: browser tries to open url <code>window.location = '/Checkout/CompleteOK'</code></p>
  
  <p>How to fix this exception? Everything looks OK, there is no partial views as described in other answers.
  I tried als o to use method='post' attribute in form but problem persists.</p>