Using Html.ActionLink and Url.Action(...) from inside Controller - asp.net-mvc

Question

I want to write an HtmlHelper to render an ActionLink with pre-set values, eg.
<%=Html.PageLink("Page 1", "page-slug");%>
where PageLink is a function that calls ActionLink with a known Action and Controller, eg. "Index" and "Page".
Since HtmlHelper and UrlHelper do not exist inside a Controller or class, how do I get the relative URL to an action from inside a class?
Update: Given the additional three years of accrued experience I have now, here's my advice: just use Html.ActionLink("My Link", new { controller = "Page", slug = "page-slug" }) or better yet,
<a href="#Url.Action("ViewPage",
new {
controller = "Page",
slug = "my-page-slug" })">My Link</a>
Your extension method may be cute and short, but it adds another untested point-of-failure and a new learning requirement for hires without adding any real value whatsoever. Think of it as designing a complex system. Why add another moving part, unless it adds reliability (no), readability (little, once you read more docs), speed (none) or concurrency (none).

Answer 1

Not sure I actually understood your question clearly, but, let me try.
To create a HtmlHelper extension like you described, try something like:
using System;
using System.Web.Mvc;
using System.Web.Mvc.Html;
namespace Something {
public static class PageLinkHelper
{
public static string PageLink(
this HtmlHelper helper,
string linkText, string actionName,
string controllerName, object routeValues,
object htmlAttributes)
{
return helper.ActionLink(
linkText, actionName, controllerName,
routeValues, htmlAttributes);
}
}
}
As for your question on getting a URL from a class, depends on what kind of class you'll implement it. For example, if you want to get the current controller and action from a HtmlHelper extension, you can use:
string currentControllerName = (string)helper.ViewContext
.RouteData.Values["controller"];
string currentActionName = (string)helper.ViewContext
.RouteData.Values["action"];
If you want to get it from a controller, you can use properties/methods from the base class (Controller) to build the URL. For example:
var url = new UrlHelper(this.ControllerContext.RequestContext);
url.Action(an_action_name, route_values);