Hi! Could you post the code for your controller? Will have a look at it tomorrow, unless you figure it out before then.

Take care and good luck!

The controller code is here

public class MembershipFormSurfaceController : BaseMembershipFormSurfaceController
{
    public MembershipFormSurfaceController()
    {
    }

    [ChildActionOnly]
    public ActionResult RenderMembershipForm()
    {
        MembershipFormViewModel model = new MembershipFormViewModel();

        MembershipSettings membershipSettingsNode = Umbraco.TypedContentSingleAtXPath("/root/settings/membershipSettings") as MembershipSettings;
        model.MembershipTypes = membershipSettingsNode.MembershipTypes;

        return PartialView("Forms/_MembershipForm", model);
    }

    [HttpPost]
    [ValidateAntiForgeryToken]
    [MultipleButton(Name = "action", Argument = "Paypal")]
    public ActionResult Paypal(MembershipFormViewModel viewModel)
    {
        return HandleMembershipForm(viewModel, PaymentMethodTypes.Paypal);
    }

    [HttpPost]
    [ValidateAntiForgeryToken]
    [MultipleButton(Name = "action", Argument = "DirectDebit")]
    public ActionResult DirectDebit(MembershipFormViewModel viewModel)
    {
        return HandleMembershipForm(viewModel, PaymentMethodTypes.DirectDebit);
    }

    [HttpPost]
    [ValidateAntiForgeryToken]
    public ActionResult HandleMembershipForm(MembershipFormViewModel viewModel, PaymentMethodTypes paymentMethod)
    {
        bool isSpam = false;

        if (!ModelState.IsValid)
        {
            return CurrentUmbracoPage();
        }

        if (!string.IsNullOrWhiteSpace(viewModel.FormCheck)) { isSpam = true; }

        if (!isSpam)
        {
            MembershipFormPage currentPage = Umbraco.AssignedContentItem as MembershipFormPage;

            // Get any services required
            var memberService = Services.MemberService;
            var contentService = Services.ContentService;

            // Get the settings node
            Settings settingsNode = Umbraco.TypedContentSingleAtXPath("/root/settings") as Settings;

            // Create the new member and assign all the form values to the member properties
            IMember member = memberService.CreateMember(viewModel.FirstName + " " + viewModel.LastName, viewModel.EmailAddress, viewModel.FirstName + " " + viewModel.LastName, "Member");
            member.IsApproved = true;
            SetMemberProperties(member, viewModel);
            SaveAttachment(member, viewModel);

            memberService.Save(member);

            memberService.AssignRole(member.Id, "Members");

            memberService.Save(member);

            // At this point we want to send the user to the PayPal system
            if (member != null && member.Key != Guid.Empty)
            {
                // send an email to the admin to let them know about the application. 
                // I think this is better here before payment as it means admin will be notified of all signups even ones that quit out before paying (so they can chase or delete from CMS)
                EmailService.SendApplicationEmails(member, currentPage);

                switch (paymentMethod)
                {
                    case PaymentMethodTypes.Paypal:
                        // Get the PayPal Provider page and forward the user to here using the correct membershipOrderReference, best to add the membership number for security
                        PayPalProvider payPalProviderNode = Umbraco.TypedContentSingleAtXPath("/root/settings/payPalProvider") as PayPalProvider;
                        Response.Redirect(payPalProviderNode.Url + "?membershipOrderReference=" + membershipOrder.OrderReference + "&membershipNumber=" + membershipOrder.MembershipNo);
                        break;
                    case PaymentMethodTypes.DirectDebit:
                        MembershipSettings membershipSettings = Umbraco.TypedContentSingleAtXPath("/root/settings/membershipSettings") as MembershipSettings;
                        Response.Redirect(membershipSettings.DirectDebitFormPage.Url + "?membershipOrderReference=" + membershipOrder.OrderReference + "&membershipNumber=" + membershipOrder.MembershipNo);
                        break;
                }

            }
        }

        return RedirectToCurrentUmbracoPage();
    }
}

BaseMembershipFormSurfaceController inherits from SurfaceController and just contains a few helper methods.

And it's called like this

@Html.Action("RenderMembershipForm", "MembershipFormSurface")

I really don't know what the client is doing that is causing the error. Think I'm going to have to get the project manager to contact them and ask tbh.

Ah, glad to hear that it worked out for you and thank you for posting the answer! Hopefully it can help someone in the future with the same problem. #h5yr

Have a great weekend!

Just wanted to swing by and said this post helped me out @suzyb, thanks for updating with the solution!

Thank you Suzyb,

I have been looking for a way to hijack the umbraco form and customize it for awhile.

What helped me was the keyworkd BeginUmbracoForm when I was using BeginForm (being a MVC developer, I never thought of anything wrong with it). So I am posting my code here, in case anyone needs help to successfully do so.

You need to make sure you can generate the model first via the appSettings.json (Under Umbraco>CMS>

 "ModelsBuilder": {
    "ModelsMode": "SourceCodeAuto",
    "AcceptUnsafeModelsDirectory": true,
    "ModelsDirectory": "~/App_Data/Models",
    "DebugLevel": 0
  },

)

Then create the controller

 public class UserEnquiryController : SurfaceController
{
    public UserEnquiryController(IUmbracoContextAccessor umbracoContextAccessor, IUmbracoDatabaseFactory databaseFactory, ServiceContext services, AppCaches appCaches, IProfilingLogger profilingLogger, IPublishedUrlProvider publishedUrlProvider) : base(umbracoContextAccessor, databaseFactory, services, appCaches, profilingLogger, publishedUrlProvider)
    {
    }

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

    [HttpPost]
    public IActionResult SubmitForm(UserEnquiry model)
    {
        if (ModelState.IsValid)
        {
            TempData.Add("Success", "true");

        }
        else
        {
           var successKey = TempData.FirstOrDefault(t=>string.Equals("Sucess",t.Key, StringComparison.InvariantCultureIgnoreCase));
            if (successKey.Value != null)
            {
                TempData.Remove(successKey);
            }
        }
        return CurrentUmbracoPage();
    }
}

And my view is below

@inherits Umbraco.Cms.Web.Common.Views.UmbracoViewPage<ContentModels.UserEnquiry>

@using Clean.Core.Models.ViewModels @using ContentModels = Umbraco.Cms.Web.Common.PublishedModels

@{ Layout = "master.cshtml"; var submitted = false; if (bool.TryParse(TempData["Success"]?.ToString() ?? "", out var success)) { submitted = true; } }

@await Html.PartialAsync("~/Views/Partials/pageHeader.cshtml", new PageHeaderViewModel(Model.Name, Model.Title, Model.Subtitle, Model.MainImage))

@Html.GetGridHtml(Model, "mainContent", "Clean")

@using (Html.BeginUmbracoForm("SubmitForm", "UserEnquiry")) { @if (submitted) {

    @if (success)
    {
        @Model.SuccessMessage
    }
    else
    {
        @Model.ErrorMessage
    }
}
else
{
    @Model.IntroductionMessage
    <div class="my-5">
        @Html.Label(Model.UserEnquiryName)
        @Html.TextBox(Model.UserEnquiryName)
        @Html.Label(Model.UserEnquiryNumber)
        @Html.TextBox(Model.UserEnquiryNumber)

       <input type="submit" class="button" value="Submit" />
    </div>
}

}

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