OK. May be I wasn't clear.
I already did the retrieving data from the SQL database and show it in TreeView as hyperlinks nodes; I used some parameters in these hyperlinks to show other data in GridView depending on these parameters. I finished from all of that, but the problem is every time I pressed the nodes, the whole page refreshed!!
I've read some articles which said you can stop the postback by using AJAX thru UpdatePanel, but it didn't worked.
I also heard that I can do it thru JavaScript, but I don't have any idea, because I'm not familiar with JavaScript.
Does anyone have any idea how to do it??
Thank you again