The PdfViewer control is tied to the browser’s controls, so it might be challenging to tie to the print preview event through the PdfViewer control.
I would suggest integrating Print.JS with your project: https://printjs.crabbly.com/
This library allows you to pass it the URL of a PDF and send it to print preview.
Does this library work for you?
Alternatively, if you’re using Mozilla pdf.js you can try the solution provided in this StackOverflow post: