Sitecore MVC controller rending parameters

public class RenderingUtil

    {

        public static string GetRenderingParameter(string parameterName)

        {

            if (RenderingContext.CurrentOrNull != null)

            {

                string parameterValue = RenderingContext.Current.Rendering.RenderingItem.Parameters;

               

                if (!string.IsNullOrEmpty(parameterValue))

                {

                    NameValueCollection parameters = StringUtil.ParseNameValueCollection(parameterValue, '&', '=');

                    string value = parameters[parameterName];

                    if (!string.IsNullOrEmpty(value))

                        return value;

                }

            }

            return parameterName;

        }

    }

=============================================================

string viewName = "FlightResultsEndOnEnd";

            if(RenderingContext.CurrentOrNull != null)

            {

                string viewParam = RenderingContext.Current.Rendering.Parameters["View"];

                if (!string.IsNullOrEmpty(viewParam))

                {

                    viewName = viewParam;

                }

            }

return View($"~/Areas/Book/Views/FlightResults/{viewName}.cshtml", fsModel);