--- title: Content Metadata properties slug: cms-13/docs/content-metadata-properties docTags: createdAt: 2026-07-30T20:22:00.693Z --- `EPiServer.Core.IContentData` is the base interface that all content models implement. All content types, except `BlockData`, also implement `EPiServer.Core.IContent`. This interface gives a content instance a unique ID and its own lifecycle: it can be loaded or saved individually. The `EPiServer.IContentRepository` performs CRUD (Create, Read, Update, Delete) operations on content instances implementing `EPiServer.Core.IContent`. Content types also implement additional metadata interfaces that define their characteristics. The following list describes each metadata interface and its properties. ## Usage Some interfaces are optional. Use the **is** or **as** operators to check whether an `IContent` instance implements an interface, as in this example: ```csharp public static CultureInfo Language(this IContent content) { if (content == null) throw new ArgumentNullException(nameof(content)); return (content is ILocale locale) ? locale.Language : CultureInfo.InvariantCulture; } public static bool IsModified(this IContent content) { if (content == null) throw new ArgumentNullException(nameof(content)); var modifiedTrackable = content as IModifiedTrackable; return modifiedTrackable == null || modifiedTrackable.IsModified; } ``` ### Shared blocks Understand how shared block instances gain `IContent` identity at runtime. `BlockData` does not implement `IContent`, but shared block instances have their own identity defined on `IContent`. At runtime, when a shared block instance is created (for example, through `IContentRepository.GetDefault` where `T` inherits from `BlockData`), Optimizely CMS creates a .NET type inheriting `T` using a technique called **mixin**. The generated subclass implements extra interfaces, including `IContent`. A shared block instance of `T` implements `IContent`, while an instance of `T` used as a property on a page does not. ## IContentData This base interface for content models contains a backing `PropertyDataCollection` used when loading or saving data from the database. - `Property` (`PropertyDataCollection`) – Contains backing data for properties used by the content instance. ## IContent This base interface gives content models their own identity, enabling individual loading and saving. `IContent` inherits `IContentData`. `ContentLink.ID` and `ContentGuid` are the same for all language branches of a content item. The combination of `ContentLink` or `ContentGuid` and `ILocale.Language` uniquely identifies the content instance (if it implements `ILocalizable`). All built-in base content types, except `BlockData`, implement `IContent`. Shared block instances implement `IContent` (and most other metadata interfaces) at runtime. - `Name` (`string`) – The name of the content instance. - `ContentLink` (`ContentReference`) – The identifier of the content instance. WorkID specifies an optional version ID, in case the instance represents a specific version. To read the version of any loaded content, use `IVersionable.Version`. - `ContentGuid` (`Guid`) – A GUID-based identifier for the content instance. - `ParentLink` (`ContentReference`) – The parent identifier (in a tree structure) for the content instance. - `ContentTypeID` (`int`) – An identifier that specifies which content type the content is an instance of. - `IsDeleted` (`bool`) – Indicates if the content instance is in the wastebasket. - `Property` (`PropertyDataCollection`) – Inherited from `IContentData`. ## IVersionable This optional interface supports different versions for each language branch. Only one version can be published at a time. Built-in types, except `ContentFolder`, implement `IVersionable`. See [Content versions](docId\:j8EP3IlASieAMVfQu5NT1). - `Status` (`VersionStatus`) – Specifies the status of the content version. - `IsPendingPublish` (`bool`) – Specifies if there is any published version for the current language branch. - `StartPublish` (`DateTime?`) – Optional value that specifies when the content is/was published. - `StopPublish` (`DateTime?`) – Optional value that specifies when the content is/was depublished. - `Version` (`int`) – Read-only value that specifies the version number (work ID) of the content version that the instance represents. The value is `0` when the instance has no saved version, such as content from a content provider without version support. Available in CMS 13.3.0 and later. Use `Version` to read the version of loaded content without calling `IContentVersionRepository`. This avoids extra database lookups when you process many content items. Optimizely CMS sets `Version` when it loads published content, a specific version, or a list of content items. It also updates `Version` when you save content. In contrast, `ContentLink.WorkID` holds a value only when you load a specific version. Built-in content types, including shared block instances, implement `Version` explicitly. Read it through the `IVersionable` interface, as in the following example: ```csharp public static int GetVersion(this IContent content) { if (content == null) throw new ArgumentNullException(nameof(content)); return (content is IVersionable versionable) ? versionable.Version : 0; } ``` Custom `IVersionable` implementations do not require changes. The interface provides a default implementation of `Version` that returns `0`. A content type that declares its own property named `Version` is not affected. ## ILocale This optional interface specifies the language of a content instance. All built-in types except `ContentFolder` implement `ILocale`. - `Language` (`CultureInfo`) – Specifies the language of a content instance. `CultureInfo.InvariantCulture` means that the content instance is not culture-specific. ## ILocalizable This optional interface supports multiple language branches. It inherits `ILocale`. All built-in types, except `ContentFolder` and `MediaData`, implement `ILocalizable`. - `Language` (`CultureInfo`) – Inherits from `ILocale`. - `MasterLanguage` (`CultureInfo`) – Specifies which language version contains the non-language-specific properties. - `ExistingLanguages` (`IEnumerable`) – Specifies all existing language branches for this content. ## IReadOnly/IReadOnly\ Implement `IReadOnly` on content types to ensure integrity when the cache serves and reuses instances across requests. All built-in base content classes implement `IReadOnly`. - `IsReadOnly` (`bool`) – Specifies if the current instance is read-only. - `void MakeReadOnly()` (`Method`) – Makes an instance read-only. - `object/T CreateWritableClone()` (`Method`) – Creates a writable clone from a read-only instance. ## IModifiedTrackable `IModifiedTrackable` improves save performance by persisting only changed data. Built-in base content classes implement `IModifiedTrackable`. - `IsModified` (`bool`) – Specifies if the current instance is modified. - `void ResetModified()` (`Method`) – Sets the content instance in a non-modified state. ## IChangeTrackable This optional interface tracks changes on content instances. All built-in base content classes implement `IChangeTrackable`. - `Created` (`DateTime`) – The date and time when the content instance was created. - `CreatedBy` (`string`) – The username of the user that created the content instance. - `Changed` (`DateTime`) – The date when the content instance was last marked as changed. - `SetChangedOnPublish` (`bool`) – Whether the Changed date should be updated on publish. - `ChangedBy` (`string`) – The username of the user that most recently changed the content instance. - `Saved` (`DateTime`) – The date and time when the content instance was last saved. - `DeletedBy` (`string`) – The username of the user who deleted the content. - `Deleted` (`DateTime?`) – The deleted date. ## IContentSecurable This optional interface supports access checks on content instances. All built-in base content classes implement `IContentSecurable`. - `IContentSecurityDescriptor` and `GetContentSecurityDescriptor()` (`Method`) – Gets the security descriptor for the content instance where access rights can be checked. ## IRoutable Content items that need routing through a content URL implement this interface. All built-in base content classes, except shared blocks, implement `IRoutable`. - `RouteSegment` (`string`) – Specifies the route segment used in the hierarchical content URL for the content instance. ## ICategorizable Content items that support categorization implement this interface. Built-in base content classes, except content folders, implement `ICategorizable`. - `Category` (`CategoryList`) – A list of all categories that this content instance is categorized as. ## IInitializableContent This optional interface sets default values when creating an instance of a content type. - `void SetDefaultValues(ContentType contentType)` (`Method`) – Called when an instance of the content type is created. ## IExportable This optional interface specifies how to handle a content instance during export. - `ShouldBeImplicitlyExported` (`bool`) – Specifies whether this instance should be implicitly added to the export package when referenced by some exported entity.