Subscribing Using Callback Mode

Perform callbacks for new data.

1. Set the subscriber options:

   NetEspSubscriberOptions options = new NetEspSubscriberOptions();
   options.set_mode(NetEspSubscriberOptions.NET_ESP_ACCESS_MODE_T.NET_CALLBACK_ACCESS);
   NetEspSubscriber subscriber = new NetEspSubscriber(options, error);
   

2. Create the callback instance:

   NetEspSubscriber.SUBSCRIBER_EVENT_CALLBACK callbackInstance = new NetEspSubscriber.SUBSCRIBER_EVENT_CALLBACK(subscriber_callback);

3. Create the callback registry:

   subscriber.set_callback(NetEspSubscriber.NET_ESP_SUBSCRIBER_EVENT.NET_ESP_SUBSCRIBER_EVENT_ALL, callbackInstance, null, error);

4. Connect to the subscriber:

   subscriber.connect(error);

5. Subscribe to a stream:

   subscriber.subscribe_stream(stream, error);
6. Implement the callback:

   Public static void subscriber_callback(NetEspSubscriberEvent event, ValueType
   data) {
   switch (evt.getType())
               {
                   case (uint)(NetEspSubscriber.NET_ESP_SUBSCRIBER_EVENT.NET_ESP_SUBSCRIBER_EVENT_CONNECTED):
                       Console.WriteLine("the callback happened: connected!");
                       break;
   (uint)( NetEspSubscriber.NET_ESP_SUBSCRIBER_EVENT.NET_ESP_SUBSCRIBER_EVENT_DATA):
   

7. (Optional) Use handleData to complete a separate method to retrieve and use subscribed data.

   NetEspRowReader row_reader = null;
   while ((row_reader = evt.getMessageReader().next_row(error)) != null) {
                   for (int i = 0; i < schema.get_numcolumns(); ++i) {
                       if ( row_reader.is_null(i) == 1) {
                           Console.Write("null, ");
                           continue;
                       }
                       switch (NetEspStream.getType(schema.get_column_type((uint)i, error)))
                       {
                           case NetEspStream.NET_DATA_TYPE_T.NET_ESP_DATATYPE_INTEGER:
                               ivalue = row_reader.get_integer(i, error);
                               Console.Write(ivalue + ", ");
                               break;
                           case NetEspStream.NET_DATA_TYPE_T.NET_ESP_DATATYPE_LONG:
                               lvalue = row_reader.get_long(i, error);
                               Console.Write(lvalue + ", ");
                               break;
                           case NetEspStream.NET_DATA_TYPE_T.NET_ESP_DATATYPE_FLOAT:
                               fvalue = row_reader.get_float(i, error);
                               Console.Write(fvalue + ", ");
                               break;
                           case NetEspStream.NET_DATA_TYPE_T.NET_ESP_DATATYPE_STRING:
                               svalue = row_reader.get_string(i, error);
                               Console.Write(svalue);
                               break;
                           case NetEspStream.NET_DATA_TYPE_T.NET_ESP_DATATYPE_SECONDDATE:
                               dvalue = row_reader.get_seconddate(i, error);
                               Console.Write(dvalue + ", ");
                               break;
                           case NetEspStream.NET_DATA_TYPE_T.NET_ESP_DATATYPE_MSDATE:
                               tvalue = row_reader.get_msdate(i, error);
                               Console.Write(tvalue + ", ");
                               break;
                           case NetEspStream.NET_DATA_TYPE_T.NET_ESP_DATATYPE_BOOLEAN:
                               boolvalue = row_reader.get_boolean(i, error);
                               Console.Write(boolvalue + ", ");
                               break;
                           case NetEspStream.NET_DATA_TYPE_T.NET_ESP_DATATYPE_BINARY:
                               uint buffersize = 256;
                               binvalue = row_reader.get_binary(i, buffersize, error);
                               Console.Write(System.Text.Encoding.Default.GetString(binvalue) + ", ");
                               break;
                           case NetEspStream.NET_DATA_TYPE_T.NET_ESP_DATATYPE_INTERVAL:
                               intervalue = row_reader.get_interval(i, error);
                               Console.Write(intervalue + ", ");
                               break;
                           case NetEspStream.NET_DATA_TYPE_T.NET_ESP_DATATYPE_MONEY01:
                               mon = row_reader.get_money(i, error);
                               Console.Write(mon.get_long(error) + ", ");
                               break;
                           case NetEspStream.NET_DATA_TYPE_T.NET_ESP_DATATYPE_MONEY02:
                               lvalue = row_reader.get_money_as_long(i, error);
                               Console.Write(lvalue + ", ");
                               break;
                           case NetEspStream.NET_DATA_TYPE_T.NET_ESP_DATATYPE_MONEY03:
                               mon = row_reader.get_money(i, error);
                               Console.Write(mon.get_long(error) + ", ");
                               break;
                           case NetEspStream.NET_DATA_TYPE_T.NET_ESP_DATATYPE_MONEY10:
                               mon = row_reader.get_money(i, error);
                               Console.Write(mon.get_long(error) + ", ");
                               break;
                           case NetEspStream.NET_DATA_TYPE_T.NET_ESP_DATATYPE_MONEY15:
                               mon = row_reader.get_money(i, error);
                               Console.Write(mon.get_long(error) + ", ");
                               break;
                           case NetEspStream.NET_DATA_TYPE_T.NET_ESP_DATATYPE_BIGDATETIME:
                               bdt2 = row_reader.get_bigdatetime(i, error);
                               long usecs = bdt2.get_microseconds(error);
                               Console.Write(usecs + ", ");
                               break;
                       }
                   }
               }
   

8. Disconnect from the subscriber:

               rc = subscriber.disconnect(error); 
   }