how to get list of Area,Action,Controller Names in Web Api

Question

consider the following code snippet. It works well in an asp.net mvc program

public IList<ActionAndControllerName> AreaAndActionAndControllerNamesList()
    {
        Assembly asm = Assembly.GetExecutingAssembly();
        var contradistinction = asm.GetTypes()
            .Where(type => typeof(Controller).IsAssignableFrom(type))
            .SelectMany(type =>
                type.GetMethods(BindingFlags.Instance | BindingFlags.DeclaredOnly | BindingFlags.Public))
            .Select(x => new
            {
                Controller = x.DeclaringType?.Name,
                Action = x.Name,
                Area = x.DeclaringType?.CustomAttributes.Where(c => c.AttributeType == typeof(AreaAttribute))
            });

        var list = new List<ActionAndControllerName>();

        foreach (var item in contradistinction)
        {
            if (item.Area.Any())
            {
                list.Add(new ActionAndControllerName()
                {
                    ControllerName = item.Controller,
                    ActionName = item.Action,
                    AreaName = item.Area.Select(v => v.ConstructorArguments[0].Value.ToString()).FirstOrDefault()
                });
            }
            
        }

        return list.Distinct().ToList();
    }

}

But returns a null when used in a web api. What needs to change?