c# - Passing combobox selected value to WCF to get data from a silverlight 5 Pivot Viewer Client -

i have combobox has list of brands, need pass selected value of combo box wcf service named service1.svc. not able understand how can pass selected item parameter service. guys please me out. thanks

my service reference follows

namespace silverlightapplication2.web {

public class service1 {      [operationcontract]     public observablecollection<employee> getallemployees(string brandid)       {         var emps = new observablecollection<employee>();         string connect = configurationmanager.connectionstrings["yoyo"].tostring();          using(var con = new odbcconnection(connect))         {               string query = "select new,brand,imagelink pivottable brand='"+brandid+"'";               var cmd = new odbccommand(query, con);               con.open();                using (var dr = cmd.executereader())             {                 while(dr.read())                 {                     var emp = new employee();                     emp.employeeid = dr.getint32(0);                     emp.firstname = dr.getstring(1);                     emp.imageuri = new uri(dr.getstring(2));                     emps.add(emp);                  }               }            }          return emps;      }   } 

}

my mainpage.xaml.cs follows

namespace silverlightapplication2 {

   public partial class mainpage : usercontrol {     public mainpage()     {         initializecomponent();         object selecteditem = combobox.selecteditem;          var proxy = new service1client(selecteditem.tostring());       //  var proxy = new service1client();         proxy.getallemployeescompleted += proxy_getallemployeescompleted;        proxy.getallemployeesasync();         var proxytwo = new service1client();        proxytwo.getallbrandscompleted += proxytwo_getallbrandscompleted;        proxytwo.getallbrandsasync();     }      void proxytwo_getallbrandscompleted(object sender, getallbrandscompletedeventargs f)     {         combobox.itemssource = f.result;     }       void proxy_getallemployeescompleted(object sender,getallemployeescompletedeventargs e)     {           pivot.itemssource = e.result;       }          private void btnadd_click(object sender, routedeventargs e)     {         object selecteditem = combobox.selecteditem;         messagebox.show("selected item is" +selecteditem.tostring());      }    } 

}

i object reference not set instance of object. @ var proxy = new service1client(selecteditem.tostring());

var proxy = new service1client();  proxy.getallemployeescompleted += proxy_getallemployeescompleted; proxy.getallemployeesasync(selecteditem.tostring()); 

if compiler errors on last line, need update service proxy. right-click service reference , select what's closest "update" in ides language.