单击特定标记时如何在地图上显示信息

我在地图上显示了1000个标记，这些标记是从datagridview中检索的。这很好，但我想在点击时在这些标记上显示文本作为客户端名称。有可能那样做吗。。。。

if（组合框5.SelectedIndex==4）//（区域1）｛

            gMapControl1.MapProvider = GMap.NET.MapProviders.GoogleMapProvider.Instance; ;
            GMap.NET.GMaps.Instance.Mode = GMap.NET.AccessMode.ServerOnly;
            GMapOverlay markersOverlay = new GMapOverlay("VCS MAP");
            gMapControl1.MaxZoom = 11;
            gMapControl1.MinZoom = 1;
            gMapControl1.Zoom = 1;
            SqlDataReader myReader;
            String Query = " SELECT  top 200 Latitude,Longitude,client name  FROM [ICPS].[dbo].[agreement latlongkir]   where region ='5' ";
            SqlConnection conDataBase = new SqlConnection(conString);
            conDataBase.Open();
            SqlCommand cmdDatabase = new SqlCommand(Query, conDataBase);
            myReader = cmdDatabase.ExecuteReader();
            gMapControl1.HoldInvalidation = true;

            while (myReader.Read())
            {
                string Latitude = myReader["Latitude"].ToString();
                string Longitude = myReader["Longitude"].ToString();
                string ClientName = myReader["client name"].ToString();
                gMapControl1.Position = new PointLatLng(float.Parse(Latitude), float.Parse(Longitude));
                GMarkerGoogle marker = new GMarkerGoogle(gMapControl1.Position, GMarkerGoogleType.pink);
                markersOverlay.Markers.Add(marker);
                gMapControl1.Overlays.Add(markersOverlay);
                marker.ToolTip = new GMapRoundedToolTip(marker);
                marker.ToolTipText = myReader("ClientName");

            }
        }

marker.ToolTipMode = MarkerTooltipMode.Always;