How to implement the Refresh method for a custom list editor that shows Google Maps in XAF ASP.NET application

[DevExpress Support Team: CLONED FROM T195734: How to use Google Maps in XAF ASP.NET application]
Hello Dennis,

I used the following custom list editor,

C#
using BeYat.BusinessObjectsLibrary.Helpers;  
using DevExpress.Data;  
using DevExpress.ExpressApp.Editors;  
using DevExpress.ExpressApp.Model;  
using DevExpress.ExpressApp.Web;  
using DevExpress.Web;  
using DevExpress.Xpo;  
using System;  
using System.Collections;  
using System.Collections.Generic;  
using System.ComponentModel;  
using System.Linq;  
using System.Text;  
using System.Threading.Tasks;  
using System.Web.UI.WebControls;  

namespace BeYat.Module.Web.Editors  
{  
    [ListEditor(typeof(IGoogleMapsMarker), true)]  
    public class ASPxGoogleMapsListEditor : ListEditor {  

        public ASPxGoogleMapsListEditor(IModelListView model) : base(model) { }  

        protected override void AssignDataSourceToControl(object dataSource) {  
            //IListSource listSource = (IListSource)dataSource;  
            //IListServer listServer = (IListServer)listSource.GetList();  
            //IList rows = listServer.GetAllFilteredAndSortedRows();  

            WebWindow.CurrentRequestWindow.RegisterClientScript(Model.Id + "_markers_script", ConvertToJS(Enumerable.Cast<IGoogleMapsMarker>((IEnumerable)dataSource)), true);  
        }  
        protected override object CreateControlsCore() {  
            return CreateGoogleMapControl();  
        }  
        public static string ConvertToJS(IGoogleMapsMarker marker) {  
            List<IGoogleMapsMarker> markers = new List<IGoogleMapsMarker>();  
            if(marker != null) {  
                markers.Add(marker);  
            }  
            return ConvertToJS(markers);  
        }  
        public static string ConvertToJS(IEnumerable<IGoogleMapsMarker> markers) {  
            string markersScript = "var markers = [";  
            if(markers != null) {  
                foreach(IGoogleMapsMarker marker in markers) {  
                    string title = (marker.Title == null) ? "" : marker.Title.Replace("'", "\\'");  
                    //markersScript += string.Format(@"{{ title: '{0}', latitude: {1}, longitude: {2} }},", title, marker.Position.Latitude, marker.Position.Longitude);  
                    markersScript += string.Format(@"{{ title: '{0}', latitude: {1}, longitude: {2} }},", title, marker.Position.Latitude.ToString().Replace(",", "."), marker.Position.Longitude.ToString().Replace(",", "."));  
                }  
            }  
            markersScript = markersScript.TrimEnd(',');  
            markersScript += "];";  
            return markersScript;  
        }  
        public static WebControl CreateGoogleMapControl() {  
            Panel ctrl = new Panel();  
            ctrl.ID = "map-canvas";  
            ctrl.Height = Unit.Percentage(100);  
            ctrl.Width = Unit.Percentage(100);  

            ASPxPanel geoMapControlPanel = new ASPxPanel();  
            geoMapControlPanel.ID = "MapPanel";  
            geoMapControlPanel.Height = new Unit(600);  
            geoMapControlPanel.Width = Unit.Percentage(100);  
            geoMapControlPanel.Controls.Add(ctrl);  

            geoMapControlPanel.Load += delegate(object sender, EventArgs e) {  
                geoMapControlPanel.ClientSideEvents.Init = @"  
                    function ShowMap() {  
                        //create empty LatLngBounds object  
                        var bounds = new google.maps.LatLngBounds();  
                        var infowindow = new google.maps.InfoWindow();  

                        var mapOptions = {  
                            center: new google.maps.LatLng(" + GoogleMapsDefaults.MapCenterLatitude.ToString().Replace(",", ".") + ", " + GoogleMapsDefaults.MapCenterLongitude.ToString().Replace(",", ".") + @"),  
                            zoom: 6,  
                        };  

                        var map = new google.maps.Map(document.getElementById('" + ctrl.ClientID + @"'), mapOptions);  

                        if (typeof markers === 'undefined') {  

                        }  
                        else {  
                            for (i = 0; i < markers.length; i++) {  
                                var data = markers[i]  
                                var latlng = new google.maps.LatLng(data.latitude, data.longitude);  
                                var marker = new google.maps.Marker({  
                                    position: latlng,  
                                    map: map,  
                                    title: data.title  
                                });  

                                //extend the bounds to include each marker's position  
                                bounds.extend(marker.position);  

                                google.maps.event.addListener(marker, 'click', (function(marker, i) {  
                                    return function() {  
                                      infowindow.setContent(locations[i][0]);  
                                      infowindow.open(map, marker);  
                                    }  
                                  })(marker, i));  
                            }  

                            //now fit the map to the newly inclusive bounds  
                            map.fitBounds(bounds);  
                        }  
                    }";  
            };  

            return geoMapControlPanel;  
        }  

        public override DevExpress.ExpressApp.Templates.IContextMenuTemplate ContextMenuTemplate {  
            get { return null; }  
        }  
        public override IList GetSelectedObjects() {  
            return new object[0];  
        }  
        public override void Refresh() {}  
        public override DevExpress.ExpressApp.SelectionType SelectionType {  
            get { return DevExpress.ExpressApp.SelectionType.None; }  
        }  
    }  
}  

and now I tried to add a couple of Filters on the ListView but when I switch from one to the other the Map doesn't refresh. But If I press refresh it works as expected.
Can you tell me how I can implement the Refresh method, because I tried the following and it doesn't work.

Thank you

C#
private ProxyCollection collection;  
private WebControl control;  


public override void Refresh() {  
    if (collection != null)  
    {  
        collection.Refresh();  
    }  
    if (control != null)  
    {  
        // nor WebControl nor AspxPanel have a refresh method  
    }  
}