How to use BizForms in Kentico 12 without page builder

Kentico 12 only supports forms using the "Form" page-builder widget out of the box.

Can anyone provide examples of how one might utilise BizForms on an MVC _Layout.cshtml or in pages that do not use the page builder?

Acceptance criteria:

• Must allow CMS users to edit the form and have the changes reflected on the site
• Must allow the developer to manipulate/transform the submitted data prior to saving to Kentico and prior to sending notifications/autoresponders
• Must correctly render custom FormSections and custom FormComponents used in the form builder

The OP posted a blog about how to make this work.

The solution requires using some of Kentico's internal APIs for Form Builder rendering with Form Widgets and putting that code into a Controller action.

var formInfo = BizFormInfoProvider
    .GetBizFormInfo(formName, SiteContext.CurrentSiteName);

string className = DataClassInfoProvider
    .GetClassName(formInfo.FormClassID);

var existingBizFormItem = className is null
    ? null
    : BizFormItemProvider
        .GetItems(className)?.GetExistingItemForContact(
           formInfo, contactContext.ContactGuid);

var formComponents = formProvider
    .GetFormComponents(formInfo)
    .GetDisplayedComponents(
      ContactManagementContext.CurrentContact, 
      formInfo, existingBizFormItem, visibilityEvaluator);

var settings = new JsonSerializerSettings
{
    ContractResolver = new CamelCasePropertyNamesContractResolver(),
    TypeNameHandling = TypeNameHandling.Auto,
    StringEscapeHandling = StringEscapeHandling.EscapeHtml
};

var formConfiguration = JsonConvert.DeserializeObject<FormBuilderConfiguration>(
    formInfo.FormBuilderLayout, settings);

return new FormWidgetViewModel
{
    DisplayValidationErrors = true,
    FormComponents = formComponents.ToList(),
    FormConfiguration = formConfiguration,
    FormName = formName,
    FormPrefix = Guid.NewGuid().ToString(),
    IsFormSubmittable = true,
    SiteForms = new List<SelectListItem>(),
    SubmitButtonImage = formInfo.FormSubmitButtonImage,
    SubmitButtonText = string.IsNullOrEmpty(formInfo.FormSubmitButtonText) 
      ? ResHelper.GetString("general.submit")
      : ResHelper.LocalizeString(formInfo.FormSubmitButtonText)
};

I took that idea and wrote a follow up post, Kentico EMS: MVC Widget Experiments Part 3 - Rendering Form Builder Forms Without Widgets, which shows we can also use Kentico's pre-built Form Widget view code to also get the expected rendering and form submission functionality.

<!-- ~/Views/Form/Form.cshtml -->

@using Kentico.Forms.Web.Mvc;
@using Kentico.Forms.Web.Mvc.Widgets;
@using Kentico.Forms.Web.Mvc.Widgets.Internal

@model FormWidgetViewModel

@{
    var config = FormWidgetRenderingConfiguration.Default;

    // @Html.Kentico().FormSubmitButton(Model) requires 
    // this ViewData value to be populated. Normally it
    // executes as part of the Widget rendering, but since
    // we aren't rendering a Widget, we have to do it manually

    ViewData.AddFormWidgetRenderingConfiguration(config);
}

@using (Html.Kentico().BeginForm(Model))
{
    @Html.Kentico().FormFields(Model)

    @Html.Kentico().FormSubmitButton(Model)
}