Creating webtest extraction rule for mvc sites querystring

Can anyone tell me how to create an extraction rule that will allow me to pull an ID from an MVC querystring?

Scenario:

User hits site, and clicks "Add new"

Request: www.site.com/item/create
Response: www.site.com/item/view/2143

The site will instantly create a new item and redirect them to the viewitem page. The id i would like to extract lives within the response after item/view/####

Current recorded code for webtest:

var request4 = new WebTestRequest((Context["WebServerAddress"] + "/Item/Create"));
request4.Method = "POST";
var request4Body = new FormPostHttpBody();
request4.Body = request4Body;
yield return request4;
request4 = null;

//server redirect response happens now

var request5 = 
  new WebTestRequest((Context["WebServerAddress"] + "/Item/Edit/?needIdForHere"));
yield return request5;
request5 = null;

Any ideas?

Many thanks,
Kohan

Solution

you may get more mileage setting the value from the WebTestContext.LastResponse.ResponseUri as an extraction rule is designed for iterating over the response body.