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I have VB.NET web page in my back-end which has a dynamically filled ASP ListBox Web Control. Is it possible to update this ListBox without Postback after the database records change by a form in modal/dialog?

Which way should I try and is there any topics related to the issue/concept?

hsobhy
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2 ways i know that could work are ajax and websockets.

Of the 2 ajax is easiest but it creates more overhead as it will be driven clientside.
Your client will submit an ajax request to the server every second, 2 seconds ...
If the server has new data it will return this data and your clientside javascript code can handle the response and create new rows etc.

Since HTML5 you can also make use of websockets. Websockets are server driven so there is no overhead. But starting a websocket server is a little more new/complicated then ajax.
Don't let that scare you though !

This is a small websocket example
Here is an ajax implementation with jquery

*update : Assuming that your are using webforms(which makes your html code more obscure and thus your solution more complex hint go mvc hint) you could also opt for asp updatePanels.
They are basicly perform an ajax call but can be a pain to implement in complex scenario's(like dynamicly generated data ;) )

*update 2: Changing your html client side can be done with jquery.
An example of adding a value to a selectbox :

$('#listbox').append('<option value="5">item 5</option>');

But beware of problems arising with the use of webforms! You're new fields and controlls will have to be compliant with asp.net webforms and this can turn out to be a pain.

Community
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Kristof
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  • Then I will not need to do the 2 seconds check if I only want to update the box once after specific popup / dialog submission for new record and so the Ajax method will be better for me .. Am I right? my question is If I have a web method and client side jQuery that updates the records how can I apply this in list element like ListBox? – hsobhy Feb 27 '14 at 12:00
  • If you have a trigger(box popup) then yes you can perform an ajax call, parse the response data and make changes on your html without the perform the ajax every X seconds. I edited my reply with a small jquery example. – Kristof Feb 27 '14 at 12:02