asp.net - Ajax AutoCompleteExtender to fire C# event -

i autocompleteextender selection fire event in code behind. i've fired onclick events javascript code before, seems steps in case. when user selects name autocompleteextender list, want take id associated name, call service more data, add gridview on page. have far...

<ajaxtoolkit:autocompleteextender id="studentnamesearchtextbox_autocompleteextender" runat="server"     targetcontrolid="studentnamesearchtextbox"      servicepath="~/scripts/autocomplete.asmx"     servicemethod="getstudents"     onclientitemselected="onstudentselected"     minimumprefixlength="2"      completionsetcount="30"      usecontextkey="true"      completionlistcssclass="autocomplete_completionlistelement"      completionlisthighlighteditemcssclass="autocomplete_highlightedlistitem"      completionlistitemcssclass="autocomplete_listitem" > </ajaxtoolkit:autocompleteextender> 

the javascript:

<script type="text/javascript">     function onstudentselected(sender, e) {         var selectedstudent = eval("(" + e._value + ")");         alert(selectedstudent); //this alerts expect         //how call singlestudentselected event, , send selectedstudent  

with?

    } </script> 

code behind:

    protected void singlestudentselected(object sender, eventargs e)     {         ///todo: data service , add grid     }  

can directly, or need have hidden button or textbox fire onchange event? accomplish cleanest way possible. thanks.

update- target textbox--

<asp:textbox id="studentnamesearchtextbox" runat="server"      cssclass="studentnamesearch" ontextchanged="studentnamesearchtextbox_textchanged"     viewstatemode="inherit"></asp:textbox> 

added javascript:

    __dopostback(sender.get_element().name, selectedstudent); 

and event:

    protected void studentnamesearchtextbox_textchanged(object sender, eventargs e)     {         ///todo: data service , add grid     }    

so, need hidden field hold selectedstudent (value of selected item) can use in studentnamesearchtextbox_textchanged event?

in opinion cleanest way save selected value hiddenfield's value, fire postback hidden button , staff in button's click event handler.