how can i make ajax work this way?

on my form, clicking on the navigation items on the left of screen will filter/refresh the gridview on the right hand side,

how can i achieve this using Ajax and not let the navigation items to reload themselves? (only the gridview refreshes)

Just make sure you only wrap the content you want to be dynamic with theUpdatePanel. That should be all you need. Start there and let us know if you're not getting what you want.

Thanks flanakin, in my applicaton, the dropdownlist has already been placed outside of UpdatePanel. the whole page reloads because the dropdownlist is "autopostback".

I found 3 lines of code that helped me to stop the whole page reload:

<Triggers>

<asp:AsyncPostBackTriggerControlID="DropDownList1"EventName="SelectedIndexChanged"/></Triggers>

I put the code inside the code of UpdatePanel, it worked, This can also be achieved by setting "Triggers" property of the UpdatePanel in design view