ConfigurationManager.ConnectionStrings (Propiedad)

// Get the ConnectionStrings section.        
// This function uses the ConnectionStrings 
// property to read the connectionStrings
// configuration section.
public static void ReadConnectionStrings()
{

  // Get the ConnectionStrings collection.
  ConnectionStringSettingsCollection connections =
      ConfigurationManager.ConnectionStrings;

  if (connections.Count != 0)
  {
    Console.WriteLine();
    Console.WriteLine("Using ConnectionStrings property.");
    Console.WriteLine("Connection strings:");

    // Get the collection elements.
    foreach (ConnectionStringSettings connection in 
      connections)
    {
      string name = connection.Name;
      string provider = connection.ProviderName;
      string connectionString = connection.ConnectionString;

      Console.WriteLine("Name:               {0}", 
        name);
      Console.WriteLine("Connection string:  {0}", 
        connectionString);
     Console.WriteLine("Provider:            {0}", 
        provider);
    }
  }
  else
  {
    Console.WriteLine();
    Console.WriteLine("No connection string is defined.");
    Console.WriteLine();
  }
}