xml中动态添加节点的问题
现在有一个xml文件如下: 
  <?xml...>  
  <configuration>  
  <appsettings>  
  <add   name= "a1 "   value= "192.168.0.1 "   active= '是 '>  </add>  
  <add   name= "a2 "   value= "192.168.0.2 "   active= '否 '>  </add>  
  </appsettings>  
  </configuration>      
 现在想在文件中动态的添加一个子节点,属性如下: 
  <add   name= "a3 "   value= "192.168.0.3 "   active= "否 ">  </add>  
 请问如何添加,谢谢!
------解决方案--------------------http://dev.csdn.net/article/69/69049.shtm