GSM ToString method

    public override string ToString()
        {
            Type thisType = this.GetType();
            // You must specify the Instance and Public flags to get the public
            //instance properties.
            //See:
            //Note: if take the static IPhone4S you get stackoverflow exception!!!
            PropertyInfo[] properties =
                thisType.GetProperties(BindingFlags.Instance | BindingFlags.Public);

            //This code is in separate private method "AppendPropertiesNamesAndValues(properties)"
            //-------------------------------------------------------------------------
            StringBuilder phoneInfo = new StringBuilder();

            phoneInfo.AppendLine("/-----Phone Info-----/\n");
            foreach (var property in properties)
            {
                var propertyValue = property.GetValue(this) ?? "null";
                phoneInfo.AppendLine(property.Name + ": " + propertyValue);
            }
            phoneInfo.AppendLine("/-------------------/");
            //-------------------------------------------------------------------------

            return phoneInfo.ToString();
        }