Question

I have a question about how ASP.NET AJAX partial rendering actually works. Does it:

1) Renders the whole page on the server, transmits the whole page to the client, the client then merges just the area contained in the update panel.

2) Renders the whole page on the server, transmits and merges just the area contained by the update panel.

3) Renders, transmits and merges just the area contained by the update panel.

Thanks,

AJ

Answer 1

2 is the answer – Partial-Page Rendering Overview:

An asynchronous postback behaves much
like a synchronous postback. All the
server page life-cycle events occur,
and view state and form data are
preserved. However, in the rendering
phase, only the contents of the
UpdatePanel control are sent to the
browser. The rest of the page remains
unchanged.