How to view xEvent event_file data
You are working under a false assumption, event_files do not store the data as XML, that is what ring_buffer does.

event_file: Data from an event_file target is displayed very well, with rich features available.
ring_buffer: Data from a ring-buffer target is displayed as raw XML.

There are a few options but for me the simplest is to put the data in a SQL database.
Once you have the data displayed in SSMS: Instance &gt; Management &gt; Extended Events &gt; Sessions &gt; [MyEvent] &gt; Package &gt; View Target data
Use the new toolbar menu item 'extended events' and export to a table in SQL database.
The database needs to exist when you export but the table does not.  I used a database named xEvent on a test/sandbox instance.
From the Toolbar: Extended Events &gt; Export to &gt; Table.. &gt; (Connect to 'test/sandbox instance' &gt; Existing database &gt; (Type in any name you like)
Use standard SQL to query.

Reference Advanced Viewing of Target Data from Extended Events in SQL Serve