AutoComplete Extender in AJAX

I am making a search functionality for text 开发者_开发知识库box using autocomplete extender. I am returning a datatable having key-value pair. I want to get the value of the text(that is Key), without using java script code, how can i achieve this? I don't want to use OnClientItemSelected of the AUTOCOMPLETE EXTENDER to get the value in hidden field form. I want to do it server side. Could some body tell me how to acheive this, or there exist better alternate way to achieve this. please let me know.

this article will help you to implement value pair autocomplete http://www.codeproject.com/KB/ajax/autosuggestextender.aspx