title: C# gmap clear all markers
body: <pre><code>  private void loadMap()
      {
          MainMap.ShowCenter = false;
  
          string cor = string.Empty;
          using (MySqlConnection sqlConn = new MySqlConnection(myConnectionString))
          {
              sqlConn.Open();
              using (MySqlCommand cmd = new MySqlCommand())
              {
                  cmd.CommandText = "SELECT * FROM event WHERE EventId=@eventId";
  
                  cmd.Connection = sqlConn;
                  cmd.Parameters.AddWithValue("@eventId", EventId);
                  using (MySqlDataReader reader = cmd.ExecuteReader())
                  {
                      while (reader.Read())
                      {
                          cor = reader.GetString("EventCor");
                      }
                  }
              }
          }
          string[] cord = cor.Split(',');
          if (cor != string.Empty)
          {
  
              Lat = Convert.ToDouble(cord[0]);
              Lng = Convert.ToDouble(cord[1]);
  
              // Initialize map:
              //GMap.NET.MapProviders.OpenCycleMapProvider
              MainMap.MapProvider = GMap.NET.MapProviders.GoogleMapProvider.Instance;
              GMap.NET.GMaps.Instance.Mode = GMap.NET.AccessMode.ServerOnly;
              MainMap.Position = new PointLatLng(Lat, Lng);
  
              GMapOverlay markersOverlay = new GMapOverlay("markers");
  
              GMarkerGoogle marker = new GMarkerGoogle(new PointLatLng(lat, lng),              
                GMarkerGoogleType.green);
  
  
              markersOverlay.Markers.Add(marker); 
              MainMap.Overlays.Add(markersOverlay);
          }
      }
  </code></pre>
  
  <p>Above is my method to load the gmap. The problem is that if i load the map again, the previous marker will remain on the map. 
  Therefore, I would like to remove all the markers on the map before loading the map.
  Thank you for your help.</p>