title: How to know the previous page?
body: <p>I have two different pages, but both goes to the same page <code>X</code>.
  When I get to the page <code>X</code>, is possible to know what was the last page? I mean, what was the page that redirected to the page <code>X</code>.</p>
  
  <p>e.g: I'm on <code>page1.aspx</code> and I have a button that redirect to <code>bonus.aspx</code>, but I also have
  <code>page2.aspx</code> that has another button but also redirect to <code>bonus.aspx</code>. Is possible to know what was the page that redirected to <code>bonus.aspx</code>? What was the last page ?</p>
  
  <p>I need to know it because i'll modify the content of <code>bonus.aspx</code> according to the previous page.</p>
  
  <p>I just want to do something like this:</p>
  
  <pre><code>protected void bonus_load(object sender, EventArgs e)
    {
       if(PreviousPage.Name == "page1.aspx")
           {
             //Do Something
           }
       else if(PreviousPage.Name == "page2.aspx")
           {
              //Do Other Things
           }
    }
  </code></pre>
  
  <p>Obs: I need to use it on a <code>button_OnClick="" Event</code></p>