title: ASP.NET: rendering content after master is already rendered
body: <p>I have a button on a content page which is suppose to modify the value of a textbox on the master page.  The setup is simple enough.</p>
  
  <p><strong>Content Page - Code Behind - Button Click Handler:</strong></p>
  
  <pre><code>protected void but_mybutton_Click(object sender, EventArgs e)
  {
      string new_value = "!!";
      Master.textbox_value(new_value);
  }
  </code></pre>
  
  <p>The problem is that by the time it get to that function, the master's page is already rendered.  To get the new value to display, I would need to re-fresh the page.  Is there anyway to explicitly tell a page to re-render because I have changed some values on it's controls without having to re-fresh the page?</p>