public void checkPhoneNumbers(List <string> numbersToCheck, Func <object, CheckNumbersCompletedEventArgs, Void> methodToCall) { numbersCheckedMethodToCall = methodToCall; try { var client = new MeetingServiceClient(new BasicHttpBinding(), new EndpointAddress(EndpointHelper.EndpointAddress)); var request = new CheckNumbersRequest { PhoneNumbers = numbersToCheck.ToArray() }; client.CheckNumbersCompleted += callNumbersCheckedDelegate; client.CheckNumbersAsync(request); } catch { MessageHelper.showErrorMesage("checkPhoneNumbers failed"); } }