public class AppEventReceiver : IRemoteEventService
    {
        /// <summary>
        /// Handles app events that occur after the app is installed or upgraded, or when app is being uninstalled.
        /// </summary>
        /// <param name="properties">Holds information about the app event.</param>
        /// <returns>Holds information returned from the app event.</returns>
        private const string ReceiverName = "ItemAddedEvent";
        private const string ListName = "test";

        public SPRemoteEventResult ProcessEvent(SPRemoteEventProperties properties)
        {

            SPRemoteEventResult result = new SPRemoteEventResult();

            switch (properties.EventType)
            {
                case SPRemoteEventType.AppInstalled:
                    HandleAppInstalled(properties);
                    break;
                case SPRemoteEventType.AppUninstalling:
                    HandleAppUninstalling(properties);
                    break;
                case SPRemoteEventType.ItemAdded:
                    HandleItemAdded(properties);
                    break;
            }


            return result;
        }

        private void HandleAppInstalled(SPRemoteEventProperties properties)

        {

            using (ClientContext clientContext =

                TokenHelper.CreateAppEventClientContext(properties, false))

            {

                if (clientContext != null)

                {

                    List myList = clientContext.Web.Lists.GetByTitle(ListName);

                    clientContext.Load(myList, p => p.EventReceivers);

                    clientContext.ExecuteQuery();



                    bool rerExists = false;



                    foreach (var rer in myList.EventReceivers)

                    {

                        if (rer.ReceiverName == ReceiverName)

                        {

                            rerExists = true;

                            System.Diagnostics.Trace.WriteLine("Found existing ItemAdded receiver at "

                                + rer.ReceiverUrl);

                        }

                    }



                    if (!rerExists)

                    {

                        EventReceiverDefinitionCreationInformation receiver =

                             new EventReceiverDefinitionCreationInformation();

                        receiver.EventType = EventReceiverType.ItemAdded;



                        //Get WCF URL where this message was handled

                        OperationContext op = OperationContext.Current;

                        Message msg = op.RequestContext.RequestMessage;

                        receiver.ReceiverUrl = msg.Headers.To.ToString();
                        receiver.ReceiverName = ReceiverName;

                        receiver.Synchronization = EventReceiverSynchronization.Synchronous;

                        myList.EventReceivers.Add(receiver);
                        clientContext.ExecuteQuery();
                      System.Diagnostics.Trace.WriteLine("Added ItemAdded receiver at "

                                  + msg.Headers.To.ToString());

                    }

                }

            }

        }