Asp.net Mvc 3 - .Net, MVC3, And Razor - Modifying ActionLink Helper?

How do I modify or create my own Html.ActionLink helper to accept and handle the first parameter (linkText) passed in as an empty string / nothing?Details: I currently have a strongly typed view that's passed a model which contains search results. My view loops through each item in the model and attempts to display a link to a contact with the following code:

@Html.ActionLink(currentItem.ContactName, "contact", "details", New With { .id = currentItem.ContactID }, Nothing)

Normally this would work just fine, but not every item in my search result has a ContactName. The Html.ActionLink helper errors when this first parameter is empty. In case it helps, here's the model property for ContactName (which is generated from a template due to Database First, so I don't believe it can be modified):

Public Property ContactName As String

I'd like to have a helper function that simply returns nothing if the ContactName is an empty string / nothing.I'm guessing I need to extend this helper, and I've struggled to find any good, up-to-date resources in VB.net for extending helper functions. Other approaches are more than welcome if they're considered best practice. I'm working in VB.net, MVC3, and Razor in the ASP.net 4.0 framework.