Why does Html.ActionLink render “?Length=4”

I’m VERY confused as to why this code

Html.ActionLink("About", "About", "Home", new { hidefocus = "hidefocus" })

results in this link:

<a hidefocus="hidefocus" href="/Home/About?Length=4">About</a>

The hidefocus part is what I was aiming to achieve, but where does the “?Length=4” come from?


The Length=4 is coming from an attempt to serialize a string object. Your code is running this ActionLink method:

public static string ActionLink(this HtmlHelper htmlHelper, string linkText, string actionName, object routeValues, object htmlAttributes)

This takes a string object “Home” for routeValues, which the MVC plumbing searches for public properties turning them into route values. In the case of a string object, the only public property is Length, and since there will be no routes defined with a Length parameter it appends the property name and value as a query string parameter. You’ll probably find if you run this from a page not on HomeController it will throw an error about a missing About action method. Try using the following:

Html.ActionLink("About", "About", new { controller = "Home" }, new { hidefocus = "hidefocus" })

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