Asp.net adding parameter to url string
<p>I'm displaying a list of filtered items in a page, and now I have to limit the displaying by paginating the results.</p>

<p>So if I have url parameters like these: </p>

<pre><code>site.com/?category=pizza&amp;period=today
</code></pre>

<p>where both category and period can also not being showed:</p>

<pre><code>site.com/?period=today

site.com/
</code></pre>

<p>how can I add a "Next page" in the end that keeps any previous parameter and adds</p>

<pre><code>&amp;pagenum=5 
</code></pre>

<p>or if there are no parameters:</p>

<pre><code>?pagenum=5
</code></pre>

<p>Tnx in advance!</p>
