Dynamic Url for the services

[JoseRamirez]

Hi, you know that for example when you add a BaseMap or you are going to use a service, generally the url is in the code. For example: ArcGISTiledMapServiceLayer tmsl = new ArcGISTiledMapServiceLayer(
   "http://services.arcgisonline.com/ArcGIS/rest/services/World_Topo_Map/MapServer");

But in my project this url can change. Is there a way to not put the url in the code and when the app start take it from a server for example. Thank you.