This topic explains how to query instances of images. The examples below show you how to query all of the available images or how to query only a specific image by its ID.
NOTE: The code examples below work with the ID of the master version of the image and return the live version of the image. For more information about other scenarios, see For developers: Query master and live versions in For developers: Content lifecycle.
Query a single image
When querying the live version of a specific image by the ID of its master version, you must perform the following:
- Get the master version.
First, get an instance of the master version with the corresponding ID.
- Get the live version.
The instance that corresponds to the ID argument is the master version of the image. You must get the live version explicitly.
NOTE: The live version is used only when displaying the news in a front-end scenario. If you want to manipulate the image, consider using the master version. To transfer the changes to the live version, publish the master version.
- Return the live version.
The following code queries the live version of an image by the ID of its master version.
First, you get an instance of the
LibrariesManager class. You get the specified image by querying all images and filtering the collection by the
Id property of the image. If the image exists, you get its live version. If no live version exists (i.e. the item has not been published), you return null. Finally, you return the live version.
You can also use the following code to retrieve the image:
NOTE: When the image does not exist, an exception of type
ItemNotFoundException is thrown.
First, you get the singular image facade of the master version with the specified ID. Then, to load the live version of the image, you call the
GetLive method of the facade. Finally, to get the instance of the live version, you call the
Query images by an album
To query images by an album, you must perform the following:
- Get the libraries manager.
Get an instance of the LibrariesManager object.
- Get the album.
Get an instance of the specified album. For more information, see For developers: Query image libraries.
- Get the images.
Get the images by calling the Images extension method of the Album instance. This extension method is located in the Telerik.Sitefinity.Modules.Libraries namespace.
NOTE: Another way of getting the images from a specific album, is to query all the images and filter the collection by the ID of the album. You can find an example of this approach in the next section.
Use the following code samples:
Query all images
When querying all images, you must perform the following:
- Query all images.
First, get a query of all available images. The query includes all live, master and temp versions.
- Filter the query.
Filter the query to return only the live versions.
- Get the images.
Get the filtered images in a list.
- Return the images.
Return the list of images.
NOTE: You can filter the query to get a specific set of images. For example, you can get the images from a specific album.
The following code queries all published images:
In this code example, you additionally filter the collection by the ID of the parent album.
NOTE: You can filter the query to get a specific set of images (as well as deleted broken images). For example, you can get the images from a specific album:
In this code example you use the plural facade for the images and filter them by the ID of the specified album. Then, you get the live versions of the selected images.