how to build a url by getting the parameter from the behind code file?
<p>Suppose I have a page named:<code>test.aspx</code>,and a behind code file <code>test.aspx.cs</code>.</p>

<p>Now ,inside the test.aspx,there is a frame whose "src" attribute is dynamic:</p>

<pre><code>&lt;iframe src="anotherPage.aspx?id=&lt;%=id%&gt;" xxx&gt;
</code></pre>

<p>the id parameter is to be explosed by the cs file
Then in the cs:</p>

<p>I have a protected field named id:</p>

<pre><code>protected strin id;
</code></pre>

<p>But it seems that it does not work?</p>

<p>What is going on?</p>
