NameValueCollection for editing query strings
<p>If I call </p>

<pre><code>var nvc = HttpUtility.ParseQueryString("?foo=bar&amp;baz=robots")
</code></pre>

<p>I get back a NameValueCollection where if I call ToString on it, I get back a query string.</p>

<pre><code>var str = nvc.ToString(); //foo=bar&amp;baz=robots....
</code></pre>

<p>If I create a new NameValueCollection, add stuff to it, and call ToString() on it, I don't get back a query string.</p>

<pre><code>var nvc= new NameValueCollection();
nvc["foo"] = "bar";
var str = nvc.ToString(); //default for Object.ToString()
</code></pre>

<p>Also there doesn't seem to be a way to construct a NameValueCollection that acts as a query string editor. Is there one? If not, why? Being able to edit query strings is a pretty useful thing, but this functionality is totally hidden away in an obscure mode of some object most people don't even know exists.</p>
