Kentico Xperience 13 documentation and ASP.NET Core

Most documentation about running Xperience applications under ASP.NET Core can be found in a dedicated section: Developing Xperience applications using ASP.NET Core. The rest of the documentation still applies, but some code samples and scenarios might need slight modifications for Core projects.

All major differences between the MVC 5 and Core platforms are summarized in Migrating to ASP.NET Core.

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Developing page templates in ASP.NET Core

Page templates allow content editors to gain greater control over the layout of pages, without the need to ask a developer to modify the code in the Core project.

Templates make it easy to choose and switch between page layouts, so they are suitable for creating pages with a predesigned or repeating structure, such as article or landing pages. Developers define the layout of these pages by preparing page templates in the code and content editors then create new landing pages based on these templates. 

Content editors can also utilize page templates 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 wish to allow editors to choose a suitable layout for each individual page.

When creating pages, content editors can choose from two types of page templates:

  • Default templates are defined in the code of the Core project. They specify the layout of a page, and the content can be then supplied by a content editor.
  • Custom templates are based on default templates. On top of the layout defined in the original default template, custom templates also contain a snapshot of page builder content, such as widgets and sections, taken from an existing page. Structured data stored in the fields of pages is not included within custom templates. See how to create custom page templates.

Page template filtering

When you register page templates in your solution, you need to implement page template filtering to limit page templates only for specific page types. Otherwise, an error occurs when creating pages of any page type with the Page builder feature enabled, but no available page template.

Creating pages that support page templates

To use page templates on your pages, you need to create and configure suitable page types and adjust the corresponding controller logic.

Start by preparing a page type for your template-based pages:

  1. Open the Page types application.
  2. Create a page type with the Page builder and URL features enabled.

Continue based on your site's routing mode:

  • On sites using content tree-based routing:
    • Basic routes handle everything for you. The system automatically initializes the data context of the page, the page builder feature, and displays the page template used by the page.
    • For 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();
              }
      

  • On sites using custom routing:
    1. Edit () the created page type and set its URL pattern.
    2. In your Core site's code, create a controller with a GET action that handles 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. Alternatively, 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);
                }
        

Note

When developing pages that use page templates, you do NOT need to create a view for the page itself. Instead, the output of the page is based on the view of the selected template.

When creating new pages of the given type in the Pages application, content editors can now select a page template. Registered page templates are automatically available for selection, depending on predefined page template filters. If only one template is available for a given page, it is selected automatically.

Implementing 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 page's layout. 

You can also 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.

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 project (not in an Area). Creating page templates in Areas may lead to unexpected behavior.

Use the following process to develop a page template:

  1. Create a view with code that defines the output of the page template according to 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 ~/PageTemplates folder, and using a view name that matches the identifier assigned to the template upon its registration prefixed with the underscore ('_') character.

    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).

  2. 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 accessed in the view by using the ComponentViewModel<TPropertyModel> class as the model.

Adding custom business logic

The basic implementation of a page template consists of only a view file (and possibly a properties class). You may need additional business logic, for example if you need to:

  • react to the configuration of the template's properties
  • perform interactions based on the page where the template is rendered
  • execute general business logic not suitable for views (e.g., database operations)

For the purpose of storing the business logic your templates require, we recommend creating dedicated service or view component classes. See the following sections for details:

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.

Service class

Separate your logic into a dedicated service class when you need to reflect the configuration of the template's properties, the context of its page, or execute general business logic not suitable for views (e.g., database operations). You can then inject the service to the template's view and call your code as required.

Use the following general process to implement a service class for a page template:

  1. Create the service class for your page template.
    • We recommend storing the service class in the ~/PageTemplates/<TemplateName> directory together with other files required by the page template. For reusable code shared across components, you can create a ~/PageTemplates/Shared directory.
  2. Implement required logic within the service class. For example, you may wish to react to the configuration of the template's properties, or the fields of the page where the template is rendered. 
    • The template's properties (if implemented) are stored in the template's model (ComponentViewModel<TPropertiesType>).
    • The current page can be accessed via the model's Page property.
  3. Register the service within the application's service container.
  4. Inject the service into the template's view file using the @inject directive.

    @inject Mysite.MyTemplateService templateService
  5. Call the service as required.

Using this approach, you can separate business and view-layer code, maintaining separation of concerns.

View component

View components can be used when you have reusable rendering logic that needs to interact with the application's business layer.

Use the following general process to implement a view component for a page template:

  1. Create a view component and its partial view.
    • We recommend storing view components related to the page template in the ~/PageTemplates/<TemplateName> directory together with other related files. For reusable code shared across components, you can create a ~/PageTemplates/Shared directory.
  2. Implement the component's InvokeAsync method. You can pass any required parameters from the template's view.
    • The template's properties (if implemented) are stored in the template's model (ComponentViewModel<TPropertiesType>).
    • The current page can be accessed via the model's Page property.  
  3. Invoke the component from within the template's view.

Using this approach, you can decouple business and view-layer code, maintaining separation of concerns.

Handling POST actions

If your page template needs to communicate with the server using POST actions, create a custom controller class containing the required methods and logic. We recommend storing the class in the ~/PageTemplates/<TemplateName> folder together with other files required by the page template.

Data of the current page rendered using the page template is 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 (or the method's Tag Helper alternative) within the given form tag in your page template view.

@using Kentico.Web.Mvc
@using Kentico.PageBuilder.Web.Mvc

<form asp-controller="TemplateController" asp-action="HandlePost" id="form">

    ...

    @Html.Kentico().PageData()

    <input type="submit" value="Submit" />
</form>

The method renders a hidden form field that persists information about the current page. The page data can be retrieved via the IPageDataContextRetriever service in the corresponding controller action. 

Obtain an instance of the IPageDataContextRetriever service (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 that contains the current page object in its Page property. You can also access the metadata and evaluate the permissions and authentication requirements of the page via the object's Metadata and Security properties.

// Holds 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 page template is placed
var article = pageDataContext.Retrieve<Article>().Page;

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).

If a page template does not require any additional services or view components, we recommend adding the registration attributes to a dedicated code file. This keeps your registrations organized. For example, you can create a file named PageTemplateRegister.cs in your project's ~/PageTemplates folder and use it to register page templates. 

When registering a page template, 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.
  • 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.cshtml")]

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.

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:

  • ~/wwwroot/PageBuilder/Public/PageTemplates/<PageTemplate> – scripts and styles intended for the live site.
  • ~/wwwroot/PageBuilder/Admin/PageTemplates/<PageTemplate> – scripts and styles intended for the administration interface (when working with the page template in the page builder editing interface).

You can use sub-folders that match the identifiers of individual templates, or a Shared sub-folder for assets used by multiple templates. Note that this recommendation only applies when using the default configuration of the bundling support provided by Xperience and may be different for your project. See Bundling static assets of builder components.

CSS notes
  • Only use the specified directories 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.

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