title: Read query string paramter from Image Url [asp.net]
body: <p>I have created a dynamic image using <code>Generic Handler[.ashx]</code> and then assigning the same to the Image on my user control from code behind.</p>
  
  <pre><code>string capt = //some random logic value.
  imgCaptcha.ImageUrl = "~/BO/term.ashx?param=" + capt;
  </code></pre>
  
  <p>Now on some button event on same usercontrol, I want to read the query parameter of the <code>ImageUrl</code></p>
  
  <pre><code> protected void btnVerify_Click(object sender, EventArgs e)
   {
       //something like this
       string param = Request.QueryString["param"]
  
   }
  </code></pre>
  
  <p>But Request.<code>QueryString</code> wont give me anything as the usercontrol is added on some <code>.aspx</code> page
  so Request path will be the same <code>.aspx</code> page which do not have the query parameters.</p>
  
  <p>But <code>imgCaptcha.ImageUrl</code> give me some path which is <code>~/BO/term.ashx?param=123456</code>.</p>
  
  <p><strong>Now I want to read this information using some .Net standard class.
  Is there anything which will solve my query?</strong> </p>
  
  <p><em>Note : I am not much interested in using string methods.</em> </p>