Generate code files for system objects

Certain types of objects in the system, such as content types, can contain custom fields used to model and structure the content stored within them (e.g., a content type object with fields for a title, article summary, and article text). These custom fields are typically assigned via the field editor or the Form Builder editing interfaces and correspond to individual database columns.

Since each object type can have a different set of custom fields, providing strongly-typed access to these fields through a shared, general class is difficult. Consequently, accessing custom field data directly often requires additional code and can be unwieldy. Developers might need to:

• Specify database column names explicitly when retrieving or manipulating data for particular fields.
• Manually perform value type conversions (e.g., from object or string) and validation on the data as it comes from the database.

To simplify working with such objects, especially when retrieving data using the ContentRetriever API or the content item query API, the system allows you to generate object-specific code files, often referred to as model classes.

A generated code file contains C# properties that directly correspond to the custom fields defined for the source object (e.g., Title, ArticleSummary, ArticleText properties for an article content type). Each property is generated with an appropriate C# data type and getter/setter logic suitable for manipulating the data of the underlying field. This provides strongly-typed access, IntelliSense support, and eliminates the need for manual type casting or validation in many cases.

Additionally, using these generated model classes greatly simplifies content retrieval. When the result type specified in a retrieval method matches the generated class for the content being retrieved, the system’s default mapping logic can often automatically populate the properties of the generated class instance directly from the query results. This reduces the need to write custom mapping logic or manually extract values from the raw database data (IContentQueryDataContainer objects).

Code generation is available for the following objects:

• Reusable content types – generates a class with the reusable content type’s fields as properties. See ContentRetriever API and Content item API to learn about available API that can be used with generated content type classes.
• Page content types – generates a class with the page content type’s fields as properties. See ContentRetriever API Content item API to learn about available API that can be used with generated page classes.
• Email content types – generates a class with the email content type’s fields as properties. Xperience currently does not provide a general API for retrieving and working with emails. Classes generated for email content types are used when retrieving the values of an email’s fields within Email Builder components.
• Reusable field schemas – generates an interface that defines the corresponding schema’s fields as its properties.
• Forms – generates a class with the form’s fields as properties. See Content retrieval to learn about available API that can be used with generated form classes.
• Object types – generates classes that facilitate working with object types. See Database table API to learn about the architecture and available API of such objects.
  • Code generation for object types can be further configured in the administration, see Configure code generation for data classes.

Generate code files

The code generator is command line-based. Code files are generated via the dotnet run --kxp-codegen .NET CLI command. You can run the generator from a command line interface of your choice (cmd, PowerShell, Bash).

Run the command from the root directory of your Xperience project:

cd my/Xperience/app/root
dotnet run --no-build -- --kxp-codegen --type "ReusableContentTypes"

The code generator supports the following parameters. You can also view the supported parameters by running the generator with the --help option:

cd my/Xperience/app/root
dotnet run -- --kxp-codegen --type "ReusableContentTypes"

dotnet run -- --kxp-codegen --type "ReusableContentTypes" --include "MyProject.Article;Acme.*"

dotnet run -- --kxp-codegen --type "ReusableContentTypes" --exclude "MyProject.Article;Acme.*"

# # Generates *Info classes only by default
dotnet run -- --kxp-codegen --type "Classes"
# Generates *Info classes along with provider classes and interfaces
dotnet run -- --kxp-codegen --type "Classes" --with-provider-class True

The system generates the code files in the specified location and folder structure.

Store generated model classes

For smaller projects, you can store generated model classes directly within the main Xperience project.

If your project consists of multiple projects or RCLs, we recommend that you create a separate Class library project for storing all generated model classes, and then reference this project from your other projects. This allows you to keep the models together (model classes often reference each other via linking properties), and ensures that the models are accessible in your entire code base.

When using the generated code files in a separate library or external application, you need to allow the system to detect the classes. Make sure class discovery is enabled for the project using the AssemblyDiscoverable attribute – see Integrate custom code.

Reusable field schema interfaces

Code files generated via ReusableContentTypes or PageContentTypes for content types that use at least one reusable field schema implement I<SchemaName> interfaces. Each such interface corresponds to a schema assigned to the given content type. You must generate these interfaces separately using the ReusableFieldSchemas --type parameter. Make sure to place them under the same namespace as the content type classes that use them. The generator outputs uncompilable code otherwise.

For example, assume an Article page content type that uses the PageMetadata and SEO reusable field schemas.

To generate the page content type, run:

dotnet run -- --kxp-codegen --type "PageContentTypes" --namespace "My.Project"

Which outputs:

namespace My.Project
{
    public partial class Article : IPageMetadata, ISEO, IWebPageFieldsSource
    {
        // Properties that represent the 'PageMetadata' and 'SEO' reusable schema fields

        // The SystemFields property

        // Properties that represent 'Article' content type fields
    }
}

To generate the corresponding reusable schema interfaces, run:

dotnet run -- --kxp-codegen --type "ReusableFieldSchemas" --namespace "My.Project"

Which outputs:

namespace My.Project
{
    public interface IPageMetadata
    {
        public const string REUSABLE_FIELD_SCHEMA_NAME = "PageMetadata";

        // Properties that represent 'PageMetadata' reusable schema fields
    }
}

namespace My.Project
{
    public interface ISEO
    {
        public const string REUSABLE_FIELD_SCHEMA_NAME = "SEO";

        // Properties that represent 'SEO' reusable schema fields
    }
}

Configure model mapping for properties storing content item references to reusable field schemas

Content types can store references to other content items via fields of the Pages and reusable content data type and the combined content selector component.

In content type model classes output by the code generator, these fields are represented as an IEnumerable collection of model classes that correspond to the content type which the field references. For example, assume the following content types:

• Book – contains information about various books (ISIN, title, etc.).
• Author – contains information about authors (name, bio, etc.) and a Books field that references content items of the Book content type (the books a given author has written).

Then the Books field, a reference from the Author content type to the Book content type, is in the generated model class represented as a property of the IEnumerable<Book> type.

If the target of the reference is not a specific content type but a reusable field schema that can be used by multiple content types, the property representing the reference is a collection of reusable field schema interface objects.

As an example, imagine a PageMetadata reusable field schema that declares fields shared by all page content types in the system. References to this schema are in generated model classes defined using the IEnumerable<IPageMetadata> type.

When retrieving content either via the ContentRetriever or content item query API and mapping the results to model classes that contain properties representing references to reusable field schemas, the system by default instantiates the referenced content items using the target reusable field schema interface type (IPageMetadata, for example).

You can override this default behavior and directly set which model class the system should use via the MapContentTypeReferenceTo and MapReferenceTo property-level attributes.

// Maps content items of the 'Blog.BLOG_CLASS_NAME' content type from the collection
// of items referenced by the 'IPageMetadata' schema to the 'Blog' model class.
[MapContentTypeReferenceTo(Blog.BLOG_CLASS_NAME, typeof(Blog))]

// Maps content items of the 'Article.ARTICLE_CLASS_NAME' content type from the
// collection of items referenced by the 'IPageMetadata' schema to the 'Article' model class.
[MapContentTypeReferenceTo(Article.ARTICLE_CLASS_NAME, typeof(Article))]

// Map all other content items to the 'PageMetadata' model class
[MapReferenceTo(typeof(PageMetadata))]

// Property representing reusable field schema references
public IEnumerable<IPageMetadata> Pages { get; set; }

// A custom implementation of the 'IPageMetadata' interface containing 
// a subset of the schema's properties.
public class PageMetadata : IPageMetadata
{
    public string PageMetadataTitle { get; set; }
}

If neither of these attributes is used, the system defaults first to the type of the property representing the reusable schema reference (IPageMetadata in the example above) and finally to the type registered via the RegisterContentTypeMapping attribute. This fallback chain is identical for both the ContentRetriever and content item query APIs.

RegisterContentTypeMapping attribute

All generated model classes come annotated with the RegisterContentTypeMapping class-level attribute. The attribute controls which model classes get prioritized when the system maps content item database data to models.

// Directs the system to use the annotated model class when model binding 
// content items of the 'DancingGoat.Coffee' content type
[RegisterContentTypeMapping("DancingGoat.Coffee")]

IContentItemFieldsSource interfaces

Classes generated for content types implement the following interfaces:

• reusable content types – IContentItemFieldsSource
• page content types – IWebPageFieldsSource (inherits from IContentItemFieldsSource)
• email content types – IEmailFieldsSource (inherits from IContentItemFieldsSource)

These interfaces are useful when accessing system properties across multiple content types, or when defining extension methods across all generated classes.

// Instance of the IContentRetriever service obtained via dependency injection
private readonly IContentRetriever contentRetriever;

public async Task<IEnumerable<IContentItemFieldsSource>> FetchMultipleContentTypes()
{
    // Gets multiple content types in a single query using IContentRetriever
    var contentTypes = new[] { Coffee.CONTENT_TYPE_NAME, Event.CONTENT_TYPE_NAME };

    // Uses 'IContentItemFieldsSource' as the shared type
    return await contentRetriever.RetrieveContentOfContentTypes<IContentItemFieldsSource>(contentTypes);
}

public static class WebPageFieldsSourceExtensionMethods
{
    public static object GetSystemProperties(this IWebPageFieldsSource source)
    {
        return new { Guid = source.SystemFields.ContentItemGUID, 
                     Id   = source.SystemFields.ContentItemID };
    }
}

Customize generated classes

In most scenarios, we do not recommend directly modifying the generated classes.

The classes as generated as partial classes. This means that you can extend them in a separate code file. Using this approach, you avoid the need to merge custom changes made to the generated code every time the class is generated again after the object’s properties are changed.

Example

namespace DancingGoat
{
    // Partial class generated by the code generator for content type 'DancingGoat.Store'
    public partial class Store : IWebPageFieldsSource
    {
        ...

        /// <summary>
        /// Store name.
        /// </summary>
        public string StoreName { get; set; }

         /// <summary>
        /// Store location.
        /// </summary>
        public string StoreLocation { get; set; }

        ...
    }
}

namespace DancingGoat
{
    // Partial class extending the generated 'Store' class
    public partial class Store
    {
        public string StoreFullName { get => $"{StoreName}-{StoreLocation}" }
    }
}