private void setFilterBt_Click(object sender, RoutedEventArgs e)
        {
            HCondition filter = new HCondition();
            HArrayOfValue valueArray = new HArrayOfValue();
            valueArray.SetName("publisher");
            JArray ja = new JArray();
            ja.Add("urn:localhost:u1");
            ja.Add("urn:localhost:u2");
            valueArray.SetValues(ja);
            filter.SetInValue(valueArray);

            Debug.WriteLine("\n-- set filer --");
            Debug.WriteLine(filter);
            Debug.WriteLine("---------------\n");
          
            //Remove the filter.
            //HCondition filter = new HCondition(JObject.Parse("{}")); 
            client.SetFilter(filter, callback);
        }