Developing page templates

Page templates allow content editors to assign page layouts when creating new pages without requiring developer assistance.

See Using page templates to see the instructions for content editors.

Page templates can also be used for creating pages with structured content (even without any page builder editable areas). This can be useful, for example, if you have multiple possible layouts for product or article pages, and want to allow content editors to choose a suitable layout for each individual page.

Example page template use cases:

Creating pages that have a similar structure or content, such as articles or landing pages.
Defining the page builder content once, then reusing it for other pages. For example, with the content reordered or modified for the new page.
Using different JavaScript, CSS, or _Layout.cshtml files for the pages of the same page type (and the structured content or page builder content defined in it).
Using pages with no content, just page builder sections that can be of a different layout for each page template.

Page template types

Default page templates are defined in the code of the live site project. Default page templates specify the layout of a page without page content.
Custom page templates are created from the page that was created using a default page template. If the page contains page builder content, such as widgets and sections, the custom page template will contain a snapshot of this content on top of the layout defined in the default page template sections. See Saving pages as custom page template.
Custom page templates do not store structured content
If the page is using structured content (the data stored in the fields of the page), this content is not saved when saving a page as a custom template.

Developers define the page layout in form of default page templates. Content creators then create a page from a default page template, or define custom page templates that inherit the layout from the default page templates. See Enable content editors to create pages based on page templates.

Enable content editors to create pages based on page templates

Create a page type that supports page templates
Design a default page template
Register the page template within the system
Implement or adjust page template filters on your site.
Filter page templates only for page types that support page templates.
If the page template filter is not correctly defined, Xperience will report an error “no available page templates” when creating a new page with any of the page types with the Page builder feature enabled.

Creating page types that support page templates

Create and configure suitable page types and adjust the corresponding logic to use page templates on your pages:

Open the Page types application.
Create a page type with the Page builder and URL features enabled.
Generate the page type wrapper classes and include them in your project. See Generating classes for Xperience objects for more information.

Modify the controller code depending on your site’s routing mode:

For sites using content tree-based routing:
1. When using basic routes, all configuration is handled by the system. The system automatically initializes the data context of the page, the page builder feature, and displays the page template used by the page.
2. When using advanced routes, action methods handling your routes need to return a TemplateResult object. You do not need to provide any parameters to the TemplateResult constructor. The router automatically provides information about the page to be rendered when handling the request.
  Handling page templates under the advanced routing scheme
```
public ActionResult Index()
{
    // Custom processing logic

    // Leverages information provided by the router when serving the request
    // to retrieve the corresponding page. No need to specify the page to render.
    return new TemplateResult();
}
```

For sites using custom routing:

Edit () the created page type and set its URL pattern.

In your live site’s code, create a controller or view component with a GET action that handles the rendering of the pages:

The GET action must return a TemplateResult object.

Pass the identifier of the page (TreeNode.DocumentID property) or the entire TreeNode object of the rendered page to the TemplateResult constructor. If you have manually initialized the page data context for the current page, you can use the parameterless TemplateResult() constructor.

Handling page templates under custom routing
private readonly IPageRetriever pagesRetriever;

// Gets instances of required services using dependency injection
public PageTemplateCustomRoutingInitialization(IPageRetriever pagesRetriever)
{
    this.pagesRetriever = pagesRetriever;
}

/// <summary>
/// A GET action displaying a page where you wish to use page templates.
/// </summary>
/// <param name="pageAlias">Page alias of the displayed page.</param>
public ActionResult Index(string pageAlias)
{
    // Retrieves a page from the Xperience database
    TreeNode page = pagesRetriever.Retrieve<TreeNode>(query => query
                        .Path("/Landing-pages", PathTypeEnum.Children)
                        .WhereEquals("NodeAlias", pageAlias)
                        .TopN(1))
                        .FirstOrDefault();

    // Responds with the HTTP 404 error when the page is not found
    if (page == null)
    {
        return HttpNotFound();
    }

    // Returns a TemplateResult object, created with the retrieved page
    // Automatically initializes the page data context and the page builder feature
    // for all editable areas placed within templates
    return new TemplateResult(page);
}

Design the default page template.
Register the default page template in the system.
If you create a page based on the default page template before the template is registered in the system will cause an error when attempting to view the page.
Delete the page and create it again after the page template is registered in the system.
Create a page template filter to filter the created page templates only for page types that support page templates specific pages.

A default page template is created. Content editors can use the page template to create new pages.

Designing default page templates

On a basic technical level, page templates are HTML pages. The main step in the development of a page template is to create a full page view that defines the output.

Within the MVC architecture, the page template view is served by a controller and a model is used to pass any required data. In many cases, templates use a default controller and view model provided by the Xperience API.

Basic page templates
Page templates with a custom controller

In both cases you can develop page templates with properties, which allow content editors to customize the template appearance in the administration interface. For templates with configurable properties, you need to create an additional model class that represents the properties and passes their values to the controller. See Defining page template properties to learn more.

MVC Areas

Page templates are designed to be used in the global scope and their code files must be placed in the application root of your MVC project (not in an MVC Area). Creating page templates in MVC Areas may lead to unexpected behavior.

Basic page templates

Use the following process to develop a page template:

Create a view with code that defines the output of the page template according to the general MVC best practices.
- The output must be a full HTML page, so the view must include the following:
  - Full HTML markup, including the html, head and body elements
  - Links to all necessary resources, such as stylesheets and scripts
  - Links to page builder scripts and styles
- Use MVC layouts with the template view for any shared output code (based on your requirements, you can use your site’s main layout, a dedicated layout for page templates, etc.).
- We recommend storing page template views in the ~/Views/Shared/PageTemplates folder, and using a view name that matches the identifier assigned to the template upon its registration prefixed with the underscore (‘_’) character. Replace any period characters (‘.’) in the identifier with underscores (‘_’) in your view name. Alternatively, you can use any required view location or name, and then specify it when registering the template.
Accessing the template’s page
If you need to work with the data of the page using the currently processed page template, use the ComponentViewModel class as the view’s model and access its Page property. The property returns a TreeNode object representing the given page. If you need to load values from the fields of a specific page type, you can convert the TreeNode object to an instance of a specific page type wrapper class (the page using the template must then be of the given page type).
Register the page template into the system. See Registering page templates.

With this approach, the template’s view is automatically displayed using a default controller provided by the Xperience API. The values of any properties defined for the template can be passed to the view by using the default ComponentViewModel<TPropertyModel> class as the model.

Example of page template development

To see a scenario with full code samples which will guide you through the process of developing a simple template, visit Example - Developing a page template with a configurable property.

Page templates with a custom controller

When developing page templates with advanced functionality, you may need to take full control over the template’s logic. You can do this by implementing the template’s controller and view model, in addition to the view. This allows you to run any custom code within the template’s controller, pass any type of required data to the view, or even switch between completely different views based on the current scenario.

The following steps describe the advanced development process for page templates:

Create a controller class for the page template.
- We recommend storing template controllers in the ~/Controllers/PageTemplates folder.
Make the controller inherit from the PageTemplateController base class (available in the Kentico.PageBuilder.Web.Mvc.PageTemplates namespace).
Implement the default Index action in the controller, which is used to retrieve the template markup. The action must return the page template’s HTML content, typically a view.
Notes
- Do not disable POST requests for the Index action (e.g., by using the HttpGet attribute). POST requests to the Index action are used in the page builder feature.
- Template controller actions used to retrieve the markup cannot be asynchronous (cannot use the async function declaration). Actions that render template markup are called as child actions when rendering the markup of a page, but MVC 5 does not support asynchronous child controller actions.
Create any required view model classes used to pass data from the template controller to the view.
- We recommend storing template models in the ~/Models/PageTemplates/<template name> folder.
Referencing actions of page template controllers
When using methods that reference page template controller actions within the code of the given view template (e.g. RedirectToAction in the controller or Html.ActionLink in views), you need to explicitly specify the controller name as a parameter of the method. For example, use RedirectToAction(actionName, controllerName) instead of RedirectToAction(actionName).
Prepare a view that defines the output of the page template according to the general MVC best practices.
- The output must be a full HTML page, so the view must include the following:
  - Full HTML markup, including the html, head and body elements
  - Links to all necessary resources, such as stylesheets and scripts
  - Links to page builder scripts and styles
- Use MVC layouts with the template view for any shared output code (based on your requirements, you can use your site’s main layout, a dedicated layout for page templates, etc.).
- We recommend storing page template views in the ~/Views/Shared/PageTemplates folder.
Register the template into the system. See Registering page templates.

With this advanced development approach, you have full responsibility and control over the template’s controller, view model, and view.

Accessing the data of the current page

If you need to access fields of the page containing the currently processed page template, obtain an instance of the IPageDataContextRetriever service (we recommend using dependency injection) and call its Retrieve<TPageType> method. Specify either a TreeNode object or a page type wrapper class as the generic parameter. The method returns an IPageDataContext<TPageType>object with the following properties:

Page – object representing the page, of the type provided in the generic parameter.
Metadata – provides access to the metadata of the page.
Security – allows you to evaluate the permissions and authentication requirements of the page. See Implementing page permission checks for details.

// Contains an instance of the IPageDataContextRetriever service (e.g., obtained via dependency injection)
private readonly IPageDataContextRetriever pageDataContext;

// Gets the page of the Article page type where the currently processed page template is placed
var article = pageDataContext.Retrieve<Article>().Page;

Accessing the data of the current page in POST actions

Data of the current page rendered using the page template are by default not accessible in controller actions that handle POST requests. Such requests do not contain sufficient information to identify the page from which they originate.

To access page data in POST actions, you need to include information about the current page into the data submitted by the corresponding form in the page template’s output – call the Html.Kentico().PageData extension method within the given form tag in your page template view.

Example
using System.Web.Mvc.Ajax
using Kentico.Web.Mvc
using Kentico.PageBuilder.Web.Mvc

...

@using (Ajax.BeginForm("PostAction", "CustomPageTemplate", null, new AjaxOptions
{
    HttpMethod = "POST",
    UpdateTargetId = "pageTemplateForm"
}, new { id = "pageTemplateForm" }))
{
    @Html.Kentico().AntiForgeryToken()
    @Html.Kentico().PageData()
    ...
    <input type="submit" value="Submit" />
}

The method renders a hidden form field that persists information about the current page. The page data can be retrieved via IPageDataContextRetriever.Retrieve<TPageType> in the corresponding POST action.

Registering page templates

Every page template needs to be registered into the system to be available. Register templates using the RegisterPageTemplate assembly attribute (available in the Kentico.PageBuilder.Web.Mvc.PageTemplates namespace).

To register Basic page templates (without a custom controller class), we recommend adding the assembly attributes to a dedicated code file. For example, you can create a file named PageBuilderComponentRegister.cs in your project’s ~/App_Start folder and use it to register your page builder components. For basic page templates, specify the following attribute parameters:

Identifier – the unique identifier of the template. We recommend using a unique prefix in your template identifiers to prevent conflicts when deploying templates to other projects, for example matching your company’s name.
Name – the name used to identify the template when displayed in the administration interface.
PropertiesType – only required for templates with properties. Specifies the System.Type of the template’s property model class.
(Optional) CustomViewName – specifies the name and location of the view that defines the template’s output. If not set, the system searches for a corresponding _<Identifier>.cshtml view in the ~/Views/Shared/PageTemplates folder (any period characters ‘.’ in the identifier are replaced by underscores ‘_’).
Basic template registration example
```
[assembly: RegisterPageTemplate("CompanyName.MyTemplate", "My template", typeof(CustomTemplateProperties), "PageTemplates/_MyTemplate")]
```

For templates with a custom controller, you can add the assembly attribute directly into the controller code file (above the controller class). In this case, specify the following attribute parameters:

Identifier – the unique identifier of the template. We recommend using a unique prefix in your template identifiers to prevent conflicts when deploying templates to other projects, for example matching your company’s name.
ControllerType – the System.Type of the template’s controller class.
Name – the name used to identify the template when displayed in the administration interface.
Controller template registration example
```
[assembly: RegisterPageTemplate("CompanyName.MyTemplate", typeof(MyTemplateController), "My template")]
```

When registering any type of page template, you can also set the following optional attribute properties:

Description – the description of the template displayed as a tooltip.
IconClass – the font icon class displayed as a thumbnail when selecting templates.

[assembly: RegisterPageTemplate("CompanyName.MyTemplate", typeof(MyTemplateController), "My template", Description = "This is a custom template.", IconClass="icon-l-img-3-cols-3")]

Localizing template metadata

To allow content editors to experience the page builder in their preferred UI culture, you can localize the Name and Description values of page templates.

Storing files for template-based pages

We recommend storing files for pages that utilize page templates in media libraries. Media library files are not bound to specific pages and their content is reusable (as opposed to page attachments). Custom page templates store only the configuration of pages, e.g. for multimedia files only the file identifiers are stored and not the files themselves. As a result, if you create a custom template from a page that displays a file, new pages created with this template will display the file only if it is stored in a media library.

Adding scripts and styles for page templates

To add JavaScript and CSS styles required by your page templates, we recommend placing script and stylesheet files into sub-folders under the ~/Content/PageTemplates directory of your MVC project (you may need to create the PageTemplatesdirectory). You can use sub-folders that match the identifiers of individual templates, or a Shared sub-folder for assets used by multiple templates.

The system does not automatically include or create bundles for .js and .css page template files. You need to include and link all custom scripts and styles for your page templates manually.

CSS notes

Only use the ~/Content/PageTemplatesdirectory to add basic styles that are required for the template to render correctly. Any site-specific styles that finalize the live site design of the template should be handled separately within the given site’s main stylesheet.
To avoid potential conflicts between styles from other third-party components, we recommend adding a unique prefix to your CSS classes and identifiers (for example #CompanyName-mid-column), or employ similar measures to ensure their uniqueness.