En este video te mostrare como puedes obtener los datos almacenados de las cadenas de conexión en tu archivo web.config o app.config en los proyectos hechos en .Net Framework.

 public class Connection
    {
        public string Server{ get; set; }
        public string User { get; set; }
        public string Password { get; set; }
        public string DB { get; set; }

        private string NameConnection;

        public Connection(string NameConnection= "pruebillaEntities")
        {
            this.NameConnection = NameConnection;
        }

        public void GetData()
        {
            ConnectionStringSettingsCollection connections = ConfigurationManager.ConnectionStrings;

            if (connections.Count > 0)
            {
                foreach (ConnectionStringSettings connection in connections)
                {
                    string name = connection.Name;
                    string provider = connection.ProviderName;
                    string connectionString = connection.ConnectionString;
                 
                    if (name.Equals(NameConnection))
                    {
                        connectionString = connectionString.Split('\"')[1];

                        string[] arrElementos = connectionString.Split(';');
                        foreach (var s in arrElementos)
                        {
                            string[] arrValue = s.Split('=');
                            switch (arrValue[0].ToUpper())
                            {
                                case "DATA SOURCE":
                                    Server = arrValue[1];
                                    break;
                                case "USER ID":
                                    User= arrValue[1];
                                    break;
                                case "PASSWORD":
                                    Password = arrValue[1];
                                    break;
                                case "INITIAL CATALOG":
                                    DB = arrValue[1];
                                    break;
                            }
                        }
                    }
                }
            }
            else
                throw new Exception("No existen cadenas de conexión");
        }

    }