Question: I know i can do this

```
var nv = HttpUtility.ParseQueryString(req.RawUrl);

```

But is there a way to convert this back to a url?

```
var newUrl = HttpUtility.Something("/page", nv);

```

Answer: 
I always use UriBuilder to convert an url with a querystring back to a valid and properly encoded url.

```
var url = "http://my-link.com?foo=bar";

var uriBuilder = new UriBuilder(url);
var query = HttpUtility.ParseQueryString(uriBuilder.Query);
query.Add("yep", "foo&bar");

uriBuilder.Query = query.ToString();
var result = uriBuilder.ToString();

// http://my-link.com:80/?foo=bar&yep=foo%26bar

```
You can use. 

```
var ur = new Uri("/page",UriKind.Relative);

```

if this nv is of type string you can append to the uri first parameter.
Like 

```
var ur2 = new Uri("/page?"+nv.ToString(),UriKind.Relative);

```