---
title: Extend meta-models
slug: commerce-connect-15/docs/extend-meta-models
docTags: 
createdAt: 2026-07-30T20:34:43.000Z
---

You can extend meta-models through the use of Modules, which is part of the meta-model that provides the main entry point in the client for extensibility objects. Install modules in the system and activate them from the meta-class.

A module consists of the following:

- **A module manifest** – Defines information about the module and references to module the configuration.
- **A module configuration** – The .NET class that implemented the `IModuleConfigurator` interface.

The Module Manager loads and calls the Module Configurator methods when a module is activated, deactivated, installed, or uninstalled. Each module should implement the Module Configurator.

:::hint{type="info"}
**Note**
You can modify a meta-model only in **Design** mode. See the `MetaClassManager` class section.
:::

Classes in this topic are available in the following namespace:

- `Mediachase.BusinessFoundation.Data.Modules`

## Change Tracking default module

The Change Tracking module adds new fields to a meta-class and registers the user and the date and time of modification. After activation, the Change Tracking module adds these meta-fields:

- `Created` – Updates this field when a new meta-object is created.
- `Modified` – Updates this field when a meta-object is modified.
- `CreatorId` – Copies the current user meta-information from `DataContext` to this field when a new meta-object is created.
- `ModifierId` – Copies the current user meta-information from `DataContext` to this field when a meta-object is modified.

To get the module manifest, call the `CreateModuleManifest` of the `ChangeTrackingManager` class.

## History default module

The History module saves meta-object modifications to the history meta-class. After activation, the `History` module creates a meta-class named `[MetaClassName]_History`, and creates a copy of the entity object if the selected field is modified. The `[MetaClassName]_History` meta-class has an `ObjectId` field that has the original primary key value.

- Call `CreateModuleManifest` of the `HistoryManager` class to get the module manifest.
- Call `SetSelectedFields` of the `HistoryManager` class, passing the meta-class, to set the collection of selected fields.
- Call `GetSelectedFields` of the `HistoryManager` class, passing the meta-class, to get the collection of selected fields.

You can read the history of the entity object from the `[MetaClassName]_History` meta-class.

## Localization default module

The Localization module localizes field values.

Do the following to define available languages after installation:

- Call `GetInstalledLanguages` of the `LocalizationManager` class to get installed languages.
- Call `InstallLanguage` of the `LocalizationManager` class passing the culture info `Name`, to install a new language.
- Call `UninstallLanguage` of the `LocalizationManager` class passing the culture info `Name`, to uninstall a language.

After activation, define the localizable field. The localization module creates a new field named `[FieldName]_[ThreeLetterWindowsLanguageName]`, which reads or saves localizable values. If the value is null, you should use the original field to get a value. When you add a new language, the localization module automatically creates new fields.

- Call `GetLocalizableFields` of the `LocalizationManager` to get localizable fields.
- Call `ActivateFieldLocalization` of the `LocalizationManager`, passing the meta-class and meta-field, to activate field localization.
- Call `DeactivateFieldLocalization` of the `LocalizationManager`, passing meta-class and meta-field, to deactivate field localization.

## Install a module

To install a new module, call `Install` of the `ModuleManager` class, passing the module manifest and attributes.

## Activate a module

To activate a module in the meta-class, call `Activate` of the `ModuleManager` class, passing the module manifest and meta-class.

## Deactivate a module

To deactivate a module, call `Deactivate` of the `ModuleManager` class, passing the module manifest and meta-class.

## Uninstall a module

To uninstall a module, call `Uninstall` of the `ModuleManager` class, passing the module manifest.