Basic MVC routing query using default project template - asp.net-mvc-3

Question

I am in the process of learning MVC 3 using the basic project template coupled with several examples I have. Things are going well, but now I am trying to implement my controllers and I am having a couple of issues.
So far I have modified the _Layout.cshtml file to have a new link with a specified route defined:
<header>
<div id="title">
<h1>My MVC Application</h1>
</div>
<div id="logindisplay">
#Html.Partial("_LogOnPartial")
</div>
<nav>
<ul id="menu">
<li>#Html.ActionLink("Home", "Index", "Home")</li>
<li>#Html.RouteLink("Contracts", "Contract")</li>
<li>#Html.ActionLink("About", "About", "Home")</li>
</ul>
</nav>
</header>
and my global.asax.cs file is as follows:
routes.MapRoute(
"Contract",
"Contract",
new { controller = "Contract", action = "List", id = UrlParameter.Optional }
);
routes.MapRoute(
"Default", // Route name
"{controller}/{action}/{id}", // URL with parameters
new { controller = "Home", action = "Index", id = UrlParameter.Optional } // Parameter defaults
);
This works fine as in it returns the expected action view from my Contract controller.
However I would like to modify this to accept an id into the List action. I know that I need to change the List method to accept a parameter, no problem there, but the issue it with the route and how to pass this paramter into the List method from the RouteLink in the _Layout.cshtml file. I have tried a few things, but this bit is really stumping me.
I intend to pass an id from the User that I logged in as through the AccountController, however I will ask another question about that to keep this more consise.
Thank you very much.

Answer 1

You don't actually need your Contract route, as your Default route will work for any controller and action that corresponds to the pattern controller/action/(optional id parameter here). See the comment in the template actually says Parameter defaults. This means, if there is no Controller, Action, or id passed in, it will default to those values. That's why you can just browse to the root of the website and the Home controller's Index action is the default call.
When using routes, you need to remember that the route parameter names need to match the parameter names in your actions.. for example, your Default route currently lets you do this:
[HttpGet]
public ActionResult MyAction(int id) {
}
But, if you changed your default route to be this:
routes.MapRoute(
"Default", // Route name
"{controller}/{action}/{myIDParameter}", // URL with parameters
new { controller = "Home", action = "Index", myIDParameter = UrlParameter.Optional } // Parameter defaults
);
..your Index action would no longer bind the integer parameter properly.. you would have to change the action to this:
[HttpGet]
public ActionResult MyAction(int myIDParameter) {
}
In answer to your question, it might make more sense to use an ActionLink, like the other two you already have:
#Html.ActionLink("Contracts", "Contract", "ActionMethodHere", new { id = UserIdHere }, null)
That assumes though, that you remove your Contract route and just use the default route.