UpdatePanel not updating back
<p>There are <code>DropDownList</code> and <code>CheckBoxList</code> in the form.<br>
The value in the DropDownList should to change depending on the choice CheckBoxList<br>
The Value in the DropDownList changes when you select (click) the element,<br>
 and if uncheck back doesn't change (it remains as high)<br>
<strong>aspx:</strong>  </p>

<pre><code> Risk:
&lt;asp:UpdatePanel ID="UpRisk" runat="server" UpdateMode="always"&gt;
 &lt;ContentTemplate&gt;
   &lt;asp:DropDownList ID="ddlRiskLevel" runat="server" Enabled="false" AutoPostBack="True"&gt;
     &lt;asp:ListItem Text="Low" Value="1" Selected="True" /&gt;
     &lt;asp:ListItem Text="High" Value="2" /&gt;
   &lt;/asp:DropDownList&gt;
 &lt;/ContentTemplate&gt;
&lt;/asp:UpdatePanel&gt;

&lt;asp:UpdatePanel ID="UpdatePanel24" runat="server" UpdateMode="always"&gt;
   &lt;ContentTemplate&gt;
         Sign:
      &lt;asp:CheckBoxList ID="chbList_Risks" runat="server"&gt;
        &lt;asp:ListItem&gt; Sign1 &lt;/asp:ListItem&gt;
        &lt;asp:ListItem&gt; Sign2 &lt;/asp:ListItem&gt;
        &lt;asp:ListItem&gt; Sign3 &lt;/asp:ListItem&gt;
      &lt;/asp:CheckBoxList&gt;
    &lt;/ContentTemplate&gt;
&lt;/asp:UpdatePanel&gt;  
</code></pre>

<p><strong>Code:</strong>  </p>

<pre><code>protected void Page_Load(object sender, EventArgs e)
{
   foreach (ListItem item in chbList_Risks.Items)
   {
       if (item.Selected)
        ddlRiskLevel.SelectedValue = "2";
   }
}
</code></pre>