Dear MVP; ASP.NET 2.0 combo box questions.

[Guest]

Greetings,

The current asp.net 1.1 combo box allow auto postback, and when this
happens, the whole page actually refreshes its self. But with the advent of
xmlhttp, we can solve this matter. Can MVP or anyone who is familiar with
asp.net 2.0 clarify this matter for me which is, does asp.net 2.0 combo box
uses xmlhttp? Which means evertime it does a postback, it does not do refresh
the entire page. Thanks in advance for you reply.

 

[Karl Seguin]

No it doesn't automatically use xmlHttp. It still does a complete postback.
The only thing which has changed is how easy it now is to use XmlHTTP
(called client callback in ASP.Net), so if you wanted to you could make your
dropdownlist use it. I wrote a real-world example/tutorial of using
client-callback in ASP.Net 2.0 with a dropdownlist, it should help shed some
light on the topic for you:
http://www.openmymind.net/clientcallback/index.html

Karl

 

[Guest]

XMLHttp is actually an older technology. You can use a web service to
"automagically" update information without a postback, but the mechanism for
controls in 2.0 is still to PostBack to the server rather than open a
connection to the server via some other mechanism.

You can set up an XMLHttp object for client side (JScript in the page) and
connect to an interface like a web service, if you wish.

NOTE: While a bit heavier than a client side mechanism, the Postback return
trip is far easier to maintain and debug. You have all of the page handling
code in one place, instead of two.

---

Gregory A. Beamer
MVP; MCP: +I, SE, SD, DBA

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