Silverlight is an RIA so the application only live on the client side. Sometime it's a good idea to store parameters on the web.config file (i.e a web service endpoint).
Of course it's impossible to read the configuration file directly from the application running on the client.
What's the workaround ?
The Silverlight application is host on an aspx page in a control. So it's possible to get a web.config item on the page loading using the ConfigurationManage :
string _baseUrl = ConfigurationManager.AppSettings["EndPointAdress"];
After you must give this parameters to the Silverlight asp.net control, you can do that via his InitParameters property :
SLControl.InitParameters = "EndPointAdress=" + _baseUrl;
Last step : get the parameter in the Silverlight application. You must do this step in the App.xaml.cs file, in the Application_Startup method :
private void Application_Startup(object sender, StartupEventArgs e)
{
string _baseUrl = e.InitParams["BaseUrl"];
}
That's all ! :)