vs2008 ajax:AjaxPanel 页面无刷新操作

<%@ Register TagPrefix="ajax" Namespace="MagicAjax.UI.Controls" Assembly="MagicAjax" %>

...

       <ajax:AjaxPanel >&nbsp; 

                        <asp:dropdownlist ></asp:dropdownlist>&nbsp;市

                             <font color="#FF0000">*</font> </td>
                      </tr>
               </ajax:AjaxPanel>

.....

  <ajax:AjaxPanel /></td>
                                </tr>
                               </table></td></tr>
                              
                                </ajax:AjaxPanel>