service - silverlight 4: setting selectedvaluepath, how do i extract it?> -

im new wcf service things im bit lost on approach here. have operation in service called getholdsjoined. listbox im binding called lbxopenholds. able set result itemsource following:

public frmholdsdashboard()         {             initializecomponent();              dbserviceclient db = new dbserviceclient();             db.getholdsjoinedcompleted +=new eventhandler<getholdsjoinedcompletedeventargs>(db_getholdsjoinedcompleted);             db.getholdsjoinedasync();          }          private void db_getholdsjoinedcompleted(object sender, getholdsjoinedcompletedeventargs e)         {             lbxopenholds.itemssource = e.result;         } 

but want set selectedvaluepath attribute in 1 of result list items. result list collection. there attribute in each 1 of list objects called a.holdid, composite. want selectedvalue member. how unbox getholdscompletedeventargs ?? or there other way this?

sorry if question asked kind of scatterbrained, didn't know how else explain it.

what this:

lbxopenholds.selectedvaluepath = "holdid"; 

this should go right after setting itemssource on lbxopenholds