model view controller - Why do these parameters not have to be supplied/given?

Question

I'm having to change an old MVC application and I'm looking through the code. For the most part I'm able to follow. I've worked on and MVC project in the past but it has been a couple of years or close to that time frame since I've been connected enough to the code to understand everything. My question is: In the below ViewResult call, why is it ok to not have supplied two of the parameters that are not nullable? To be specific (if it matters): The 1st parameter: "physicalID" is supplied. The other two that are not nullable: sortColumn and sortDirection don't appear to be supplied when this method is hit, but I don't understand/can't recall why that/this is allowed.

public ViewResult ResultDetail(int physicalID, string sortColumn, string sortDirection, int? pageNumber, int? siteID, int? clientID, int? globalEmployeeID, bool? logView){...}

Answer 1

等待大神解答