When accessing the edit view in Optimizely Content Management System (CMS), you can select a PDF document from a media folder, to preview its content.

In the _PdfPreview_ package, there is a class named `PdfFile` which handles uploaded files with the .pdf extension.

## Requirements

• No additional license fee for the add-on.

• An Optimizely Content Management System (CMS) website with the _EPiServer.PdfPreview_ package installed.

• See [Add-ons platform compatibility](🔗) for package and version information. 

## Install

• Installed through [NuGet](🔗).

PDF Preview is useful for websites where you manage multiple content items in PDF format.

## User scenarios

These are the typical user scenarios for adding PDF preview to your solution.

### The system does not have a model for handling PDF files

If the system does not have a model for handling PDF files, the default `PdfFile` model provided by the package is used. Editors can now preview PDF files in edit view without any extra steps.

### The system already has a model for handling PDF files

By default, the `ContentMediaResolver` class from CMS Core gets the first matching media implementation type registered for an extension. If there is an existing type registered for “pdf”, the `PdfFile` media implementation in the Optimizely package is used but in this case, the existing type should be chosen in this case.

To change this default behavior, a media resolver class named `PdfContentMediaResolver` is used to ignore the `PdfFile` type in the Optimizely package and thus, the existing registered media type is the candidate.

`PdfContentMediaResolver` inherits `ContentMediaResolver` and overrides the Type `GetFirstMatching(string extension)` method to handle the business logic above.

To turn on the PDF preview, the PDF media model must implement the `IPdfFile` interface. For example:

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Note

Due to limitations, after installing the add-on, you can preview only newly uploaded PDFs. You must upload existing PDFs again to be previewed.