Inheritance: SuperMap.WinRT.Mapping.TiledCachedLayer
 private async void SetCacheFolder(TileTDTMapsLayer layer)
 {
     string mapName = string.Empty;
     if (layer.IsLabel)
     {
         mapName += "Label";
     }
     else
     {
         mapName += "Map";
     }
     mapName += "_" + m_layerType + "_" + m_projection;
     layer.LocalStorage = new OfflineStorage(mapName);
 }
 //移除图层重新加载
 private void RefreshMap()
 {
     myMap.Layers.Clear();
     TileTDTMapsLayer layer1 = new TileTDTMapsLayer();
     layer1.LayerType = m_layerType;
     layer1.Projection = m_projection;
     TileTDTMapsLayer layer2 = new TileTDTMapsLayer();
     layer2.IsLabel = true;
     layer2.LayerType = m_layerType;
     layer2.Projection = m_projection;
     myMap.Layers.Add(layer1);
     myMap.Layers.Add(layer2);
     SetCacheFolder(layer1);
     SetCacheFolder(layer2);
 }