title: ASP.NET DropDownList OnSelectedIndexChanged event not fired
body: <p>I'm trying to use some AJAX and ASP.Net together to enable me to run functions without having to refresh the whole page but i've stumbled across a problem in doing this</p>
  
  <p>Here's my code</p>
  
  <pre><code>&lt;asp:ScriptManager ID="ScriptManager1" runat="server"&gt;
  &lt;/asp:ScriptManager&gt;
  
  &lt;asp:UpdatePanel ID="UpdatePanel1" runat="server"&gt;
      &lt;ContentTemplate&gt;
          &lt;asp:DropDownList ID="ddl1" runat="server" OnSelectedIndexChanged="update1" /&gt;
  
          &lt;asp:TextBox runat="server" ID="txt1" /&gt;
  
      &lt;/ContentTemplate&gt;
  &lt;/asp:UpdatePanel&gt;
  </code></pre>
  
  <p>And here's my code behind</p>
  
  <pre><code> Sub update1(ByVal sender As Object, ByVal e As EventArgs)
  
      txt1.Text = Now.ToString
  
  End Sub
  </code></pre>
  
  <p>The event doesn't fire because I don't have <code>AutoPostBack="True"</code> on my ddl but adding that to the ddl will postback the whole page.</p>
  
  <p>Is there a way to avoid using <code>AutoPostBack="True"</code> so that it only updates the panel?</p>
  
  <p>I know I can use an <code>asp:Button</code> to get around this but i'd really like to be able to use a ddl with <code>OnSelectedIndexChanged</code></p>
  
  <p>Thanks</p>