title: How to avoid page refresh after selectedindexchanged of dropdown list?
body: <p>I am using update panel and ASP drop down. When I select any value from a drop down list I load some data from a database that depends on this selected value. However, whenever this selection changes the page will be refreshed. How can I avoid this page refresh? I have also tried AsyncPostBackTrigger but still this problem occurs.</p>
  
  <pre><code>&lt;asp:ToolkitScriptManager ID="ToolkitScriptManager1" runat="server" EnablePartialRendering="false"&gt;
     &lt;/asp:ToolkitScriptManager&gt;
          &lt;asp:UpdatePanel ID="OuterUpdatePanel" runat="server"&gt;
              &lt;ContentTemplate&gt;
                  &lt;asp:DropDownList ID="ddList" CssClass="dropdown" Style="width: 200px !important;"
                   runat="server" AutoPostBack="true" OnSelectedIndexChanged="ddList_SelectedIndexChanged"&gt;
                  &lt;/asp:DropDownList&gt;
              &lt;/ContentTemplate&gt;
          &lt;/asp:UpdatePanel&gt;
  </code></pre>