(1) Printing PDF Files.
Thanks for contacting support. Please visit the following link for related information on Working with PDF printing (Facades)
(2) Concatenation of more than one PDF files.
Please visit Concatenate PDF Files
(3) Bookmarks added to PDF Files.
Please visit the following link for related information on Working with Bookmarks
(4) PDF viewer
I am afraid Aspose.Pdf for .NET does not offer the feature to view/display PDF files. However you can convert PDF pages to Image format and display image files in Image control. For further information, please visit Convert PDF Pages to JPEG Images