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

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 MVC 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 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 MVC 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 MVC 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 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 can utilize a default controller and view model provided by the Xperience API. See the following scenarios for more information:

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:

  1. 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).

  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 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:

  1. Create a controller class for the page template.
    • We recommend storing template controllers in the ~/Controllers/PageTemplates folder.
  2. Make the controller inherit from the PageTemplateController base class (available in the Kentico.PageBuilder.Web.Mvc.PageTemplates namespace).
  3. 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.
  4. 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).

  5. 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.
  6. 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:

// 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 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 PageTemplates directory). 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/PageTemplates directory 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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