asp.net 读取并修改config文件实现代码

<connectionStrings> 
<clear /> 
<addname="conJxcBook" 
connectionString="Data Source=localhost;Initial Catalog=jxcbook;User ID=sa;password=********" 
providerName="System.Data.SqlClient" /> 
</connectionStrings>

<appSettings> 
<clear /> 
<addkey="userName"value="" /> 
<addkey="password"value="" /> 
<addkey="Department"value="" /> 
<addkey="returnValue"value="" /> 
<addkey="pwdPattern"value="" /> 
<addkey="userPattern"value="" /> 
</appSettings>

///<summary> 
///依据连接串名字connectionName返回数据连接字符串 
///</summary> 
///<param name="connectionName"></param> 
///<returns></returns> 
private static string GetConnectionStringsConfig(string connectionName) 
{ 
string connectionString = 
ConfigurationManager.ConnectionStrings[connectionName].ConnectionString.ToString(); 
Console.WriteLine(connectionString); 
return connectionString; 
}

///<summary> 
///更新连接字符串 
///</summary> 
///<param name="newName">连接字符串名称</param> 
///<param name="newConString">连接字符串内容</param> 
///<param name="newProviderName">数据提供程序名称</param> 
private static void UpdateConnectionStringsConfig(string newName, 
string newConString, 
string newProviderName) 
{ 
bool isModified = false; //记录该连接串是否已经存在 
//如果要更改的连接串已经存在 
if (ConfigurationManager.ConnectionStrings[newName] != null) 
{ 
isModified = true; 
} 
//新建一个连接字符串实例 
ConnectionStringSettings mySettings = 
new ConnectionStringSettings(newName, newConString, newProviderName); 
// 打开可执行的配置文件*.exe.config 
Configuration config = 
ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None); 
// 如果连接串已存在，首先删除它 
if (isModified) 
{ 
config.ConnectionStrings.ConnectionStrings.Remove(newName); 
} 
// 将新的连接串添加到配置文件中. 
config.ConnectionStrings.ConnectionStrings.Add(mySettings); 
// 保存对配置文件所作的更改 
config.Save(ConfigurationSaveMode.Modified); 
// 强制重新载入配置文件的ConnectionStrings配置节 
ConfigurationManager.RefreshSection("ConnectionStrings"); 
}

///<summary> 
///返回＊.exe.config文件中appSettings配置节的value项 
///</summary> 
///<param name="strKey"></param> 
///<returns></returns> 
private static string GetAppConfig(string strKey) 
{ 
foreach (string key in ConfigurationManager.AppSettings) 
{ 
if (key == strKey) 
{ 
return ConfigurationManager.AppSettings[strKey]; 
} 
} 
return null; 
}

///<summary> 
///在＊.exe.config文件中appSettings配置节增加一对键、值对 
///</summary> 
///<param name="newKey"></param> 
///<param name="newValue"></param> 
private static void UpdateAppConfig(string newKey, string newValue) 
{ 
bool isModified = false; 
foreach (string key in ConfigurationManager.AppSettings) 
{ 
if(key==newKey) 
{ 
isModified = true; 
} 
} 

// Open App.Config of executable 
Configuration config = 
ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None); 
// You need to remove the old settings object before you can replace it 
if (isModified) 
{ 
config.AppSettings.Settings.Remove(newKey); 
} 
// Add an Application Setting. 
config.AppSettings.Settings.Add(newKey,newValue); 
// Save the changes in App.config file. 
config.Save(ConfigurationSaveMode.Modified); 
// Force a reload of a changed section. 
ConfigurationManager.RefreshSection("appSettings"); 
}

/// <summary> 
/// 写入Key，Value 到XML文件 
/// </summary> 
/// <param name="Key"></param> 
/// <param name="Value"></param> 
public static void SaveConfig(string Key,string Value) 
{ 
XmlDocument doc = new XmlDocument(); 
//获得配置文件的全路径 
string strFileName = AppDomain.CurrentDomain.BaseDirectory.ToString() + "App.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 == Key) 
{ 
//对目标元素中的第二个属性赋值 
att = nodes[i].Attributes["value"]; 

att.Value = Value; 
break; 
} 
} 
//保存上面的修改 
doc.Save(strFileName); 

}