how to delete calender events in google api

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.NET

I am using Google API for read,write ,delete events in Google calendar,read and write operation is working,but delete event operation is not working, give me solution and my source are given below.
advance thanks

private void Delete_Click(object sender, EventArgs e)
        {
            try
            {

      
               
                CalendarService oCalendarService = GAuthenticate();
                

                //Search for Event
                EventQuery oEventQuery = new EventQuery( new Uri("http://www.google.com/calendar/feeds/" + ((CalendarEntry)(GoogleCalendar.SelectedItem)).SelfUri.ToString().Substring(((CalendarEntry)(GoogleCalendar.SelectedItem)).SelfUri.ToString().LastIndexOf("/") + 1) + "/private/full").ToString ());
                oEventQuery.ExtraParameters = location.Text;

                Google.GData.Calendar.EventFeed oEventFeed = oCalendarService.Query(oEventQuery);

         
                //Delete Related Events
                foreach (EventEntry oEventEntry in oEventFeed.Entries)
                {

                    
                    oEventEntry.Delete();
                    break;
                }

            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }


        }
 private CalendarService GAuthenticate()
        {
            string sGoogleUserName = UserName.Text;
            string sGooglePassword = Password.Text;
            Uri oCalendarUri = new Uri(new Uri("http://www.google.com/calendar/feeds/" + ((CalendarEntry)(GoogleCalendar.SelectedItem)).SelfUri.ToString().Substring(((CalendarEntry)(GoogleCalendar.SelectedItem)).SelfUri.ToString().LastIndexOf("/") + 1) + "/private/full").ToString());

            //Initialize Calendar Service
            CalendarService oCalendarService = new CalendarService("CalendarSampleApp");
            oCalendarService.setUserCredentials(sGoogleUserName, sGooglePassword);

            //Use Proxy 
            GDataRequestFactory oRequestFactory = (GDataRequestFactory)oCalendarService.RequestFactory;
            WebProxy oWebProxy = new WebProxy(WebRequest.DefaultWebProxy.GetProxy(oCalendarUri));
            oWebProxy.Credentials = CredentialCache.DefaultCredentials;
            oWebProxy.UseDefaultCredentials = true;
            oRequestFactory.Proxy = oWebProxy;

            return oCalendarService;
        }