I’m afraid there’s no way to prevent the master page from reloading after
At run time, master pages are handled in the following sequence:
1. Users request a page by typing the URL of the content page.
2. When the page is fetched, the @ Page directive is read. If the directive
references a master page, the master page is read as well. If this is the
first time the pages have been requested, both pages are compiled.
3. The master page with the updated content is merged into the control tree
of the content page.
4. The content of individual Content controls is merged into the
corresponding ContentPlaceHolder control in the master page.
5. The resulting merged page is rendered to the browser.
From the browser’s point of view, it’s a single html page, so there’s no
way to only reload a part of it if it’s posted back.