Extension method for getting Route data in ASP.NET MVC Razor pages

RouteDataExtensions.cs

public static class RouteDataExtensions
{
    // Usage can be seen here: http://www.dvolve.org/2016/01/getting-route-data-in-asp-net-razor/
    public static bool Contains(this RouteData route, string action = null, string controller = null, string area = null, StringComparison comparison = StringComparison.CurrentCultureIgnoreCase)
    {
        // Get the parts that we'll check.
        var areaToCheck = route.DataTokens["Area"];
        var actionToCheck = route.Values.ContainsKey("Action") ? route.Values["Action"] : null;
        var controllerToCheck = route.Values.ContainsKey("Controller") ? route.Values["Controller"] : null;

        // No data is provided, so this is always true.
        if (controllerToCheck == null && actionToCheck == null && areaToCheck == null) return true;

        // Check which pieces match
        var actionMatches = string.Equals(action, (string)actionToCheck, comparison) || action == null || action == "*";
        var controllerMatches = string.Equals(controller, (string)controllerToCheck, comparison) || controller == null || controller == "*";
        var areaResult = string.Equals(area, (string)areaToCheck, comparison) || (area == "" && areaToCheck == null) || area == "*";

        // Return the result
        return actionMatches && controllerMatches && areaResult;
    }
}