If you’re writing an HTML Helper for ASP.NET MVC you may want to do something different based on whether the page that is to be rendered was arrived at via a particular controller or controller action. I found the following code which does just this in one of the ASP.NET MVC Themes available from the www.asp.net web site (the Dark theme, I believe it’s called).

Note that I’ve already modified this code to work with the new ASP.NET 4 string encoding and the MvcHtmlString type, as I wrote about previously.

<span style="color: #0000ff">public</span> <span style="color: #0000ff">static</span> MvcHtmlString LoginLink(<span style="color: #0000ff">this</span> HtmlHelper helper)
{
<span style="color: #0000ff">string</span> currentControllerName = 
(<span style="color: #0000ff">string</span>)helper.ViewContext.RouteData.Values[<span style="color: #006080">&quot;controller&quot;</span>];
&#160;
<span style="color: #0000ff">string</span> currentActionName = 
(<span style="color: #0000ff">string</span>)helper.ViewContext.RouteData.Values[<span style="color: #006080">&quot;action&quot;</span>];

&#160;
<span style="color: #0000ff">bool</span> isAuthenticated = 
helper.ViewContext.HttpContext.Request.IsAuthenticated;
<span style="color: #008000">// more stuff here</span>

}

As you can see, the HtmlHelper has a ViewContext property, which allows you to access RouteData and ultimately from there determine the controller and/or action that was used for this request. Incidentally, you can also use the ViewContext to get to HttpContext and determine whether the request is authenticated as well.

And that’s it!

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