在线跪求XML读写操作
web.config
<?xml   version= "1.0 "?>

<configuration   xmlns= "http://schemas.microsoft.com/.NetConfiguration/v2.0 ">
    <appSettings>
        <add   key= "open "   value= "T "   />
        <add   key= "allownewuser "   value= "F "   > </add>
        <add   key= "allowupload "   value= "F "   />
        <add   key= "allow "   value= "F "   />
    </appSettings>
<connectionStrings/>
   
<system.web>

<customErrors   mode= "Off "   />
    <globalization   culture= "zh-CN "   uiCulture= "zh-CHS "   />
    <compilation   debug= "true "   defaultLanguage= "c# "   />
<httpRuntime   maxRequestLength= "2000000 "   executionTimeout= "240 "/>
</system.web>
</configuration>

怎样对open,allownewuser等进行读写~在线等   谢谢

------解决方案--------------------
ConfigurationSettings.AppSettings[ "open "])
------解决方案--------------------
xmlElement.Attributes[ "value "].Value= “F”


------解决方案--------------------
string filename=Server.MapPath( "web.config ");
string KeyName;//键名称
XmlDocument xmldoc= new XmlDocument();
XmlNodeList DocdNodeNameArr=xmldoc.DocumentElement.ChildNodes;//文档节点名称数组
foreach(XmlElement DocXmlElement in DocdNodeNameArr)
{
if(DocXmlElement.Name.ToLower()== "appsettings ")//找到名称为 appsettings 的节点
{
XmlNodeList KeyNameArr=DocXmlElement.ChildNodes;//子节点名称数组
if ( KeyNameArr.Count > 0 )
{
foreach(XmlElement xmlElement in KeyNameArr)
{
KeyName=xmlElement.Attributes[ "key "].InnerXml;//键值
switch(KeyName)
{
case "open ":
xmlElement.Attributes[ "value "].Value= "F ";
break;

case "allownewuser ":
xmlElement.Attributes[ "value "].Value= "F ";
break;
//......略
}
}
}
}
}

xmldoc.Save(filename);
Response.Write( " <script> alert( 'OK,信息已保存! ') </script> ");}
------解决方案--------------------
protected void Button1_Click(object sender, EventArgs e)
{
XmlDocument doc = new XmlDocument();
//获得配置文件的全路径
string strFileName = Server.MapPath( "~ ") + @ "/Web.config ";

doc.Load(strFileName);
//找出名称为“add”的所有元素
XmlNodeList nodes = doc.GetElementsByTagName( "add ");
for (int i = 0; i < nodes.Count; i++)
{
//获得将当前元素的key属性
XmlAttribute att = nodes[i].Attributes[ "key "];
//根据元素的第一个属性来判断当前的元素是不是目标元素
if (att.Value == "open ")
{
//对目标元素中的第二个属性赋值
att = nodes[i].Attributes[ "value "];
att.Value = "F ";
break;
}
}