title: ASP.NET Update datalist by timer is not working
body: <p>I have an <code>updatepanel</code> with a <code>label</code> and a <code>datalist</code> inside as follows</p>
  <pre><code>&lt;asp:UpdatePanel ID=&quot;UpdatePanel1&quot; UpdateMode=&quot;Conditional&quot; runat=&quot;server&quot;&gt;     
    &lt;ContentTemplate&gt;    
        &lt;asp:Timer ID=&quot;Timer1&quot; runat=&quot;server&quot; Interval=&quot;2000&quot; Enabled=&quot;True&quot; ontick=&quot;Timer1_Tick&quot;&gt;&lt;/asp:Timer&gt;
        Tick &lt;asp:Label ID=&quot;LabelTick&quot; runat=&quot;server&quot; Text=&quot;&quot;&gt;&lt;/asp:Label&gt;
        &lt;asp:DataList ID=&quot;dl1&quot; runat=&quot;server&quot; DataSourceID=&quot;SqlDataSource1&quot; RepeatColumns = &quot;4&quot; CellSpacing = &quot;3&quot; RepeatLayout = &quot;Table&quot;&gt;
           &lt;ItemTemplate&gt;
              ...
           &lt;/ItemTemplate&gt;
        &lt;/asp:DataList&gt;
        &lt;asp:SqlDataSource ID=&quot;SqlDataSource1&quot; runat=&quot;server&quot; ConnectionString=&quot;&lt;%$ ConnectionStrings:MyConnectionString %&gt;&quot; SelectCommand=&quot;SELECT ...&quot;&gt;&lt;/asp:SqlDataSource&gt; 
     &lt;/ContentTemplate&gt;
  &lt;/asp:UpdatePanel&gt;
  </code></pre>
  <p>In the code-behind I update the databind after every tick:</p>
  <pre><code>Protected Sub Timer1_Tick(ByVal sender As Object, ByVal e As EventArgs) Handles Timer1.Tick
  
      dl1.DataSourceID = SqlDataSource1.ID
      dl1.DataBind()
  
      LabelTick.Text = DateTime.Now.ToString()
  
  End Sub
  </code></pre>
  <p>The <code>label</code> is updated correctly every 2 seconds, which means the timer runs correctly. But the <code>DataList</code> is not refreshed, it is only refreshed once after page load.
  Why?</p>