void downloader_OpenReadCompleted(object sender, OpenReadCompletedEventArgs e)
{
//JsonArray jsonArray = (JsonArray)JsonArray.Load(e.Result);
//JsonObject jsonArray = (JsonObject)JsonObject.Load(e.Result);
//var query = from layer in jsonArray
// select new CensusLayer
// {
// //LayerName = (string)layer["name"],
// //MapType = (string)layer["type"]
// };
//List<CensusLayer> layers = query.ToList() as List<CensusLayer>;
//ComboBox1.ItemsSource = layers;
}