Config 文件的增删改查

转自：http://hi.baidu.com/yufeng0103/blog/item/b5dc3225f8c43c6d35a80f41.html
asp.net2.0新添加了对web.config直接操作的功能。开发的时候有可能用到在web.config里设置配置文件，其实是可以通过程序来设置这些配置节的。
asp.net2.0需要添加引用：
using System.Web.Configuration;
web.config里的配置节：
<appSettings>
<add key="FilePath" value="g:/Test/WebConfigManager/Upload/" />
<add key="p" value="g:/" />
</appSettings>
（1）读
string filepath = ConfigurationManager.AppSettings["FilePath"];
（2）添加
Configuration config = WebConfigurationManager.OpenWebConfiguration("/WebConfigManager");
AppSettingsSection app = config.AppSettings;
app.Settings.Add("p", "p://");
config.Save(ConfigurationSaveMode.Modified);
（3）修改
Configuration config = WebConfigurationManager.OpenWebConfiguration("/WebConfigManager");
AppSettingsSection app = config.AppSettings;
app.Settings["p"].Value = @"g:/";
config.Save(ConfigurationSaveMode.Modified);
（4）删除
Configuration config = WebConfigurationManager.OpenWebConfiguration("/WebConfigManager");
AppSettingsSection app = config.AppSettings;
app.Settings.Remove("p");
config.Save(ConfigurationSaveMode.Modified);
注意：
（1）asp.net用户需要有读取、修改、写入的权限。
（2）WebConfigManager是web.config所在的文件夹名。

1. 读取值：
* Asp.Net: System.Web.Configuration.WebConfigurationManager.AppSettings[“y”];
* WinForm: System.Configuration.ConfigurationManager.AppSettings[“y”];
2. 添加一项
ASP.NET(需要有写权限):
Configuration config = WebConfigurationManager.OpenWebConfiguration(null);
AppSettingsSection app = config.AppSettings;
app.Settings.Add("x", "this is X");
config.Save(ConfigurationSaveMode.Modified);
WinForm:
Configuration config = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None);
AppSettingsSection app = config.AppSettings;
app.Settings.Add("x", "this is X");
config.Save(ConfigurationSaveMode.Modified);

3. 修改一项
* Asp.Net
Configuration config = WebConfigurationManager.OpenWebConfiguration(null);
AppSettingsSection app = config.AppSettings;
//app.Settings.Add("x", "this is X");
app.Settings["x"].Value = "this is not Y";
config.Save(ConfigurationSaveMode.Modified);
* WinForm
Configuration config = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None);
AppSettingsSection app = config.AppSettings;
//app.Settings.Add("x", "this is X");
app.Settings["x"].Value = "this is not Y";
config.Save(ConfigurationSaveMode.Modified);
4. 删除一项
* Asp.Net
Configuration config = WebConfigurationManager.OpenWebConfiguration(null);
AppSettingsSection app = config.AppSettings;
app.Settings.Remove("x");
config.Save(ConfigurationSaveMode.Modified);
* WinForm
Configuration config = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None);
AppSettingsSection app = config.AppSettings;
app.Settings.Remove("x");
config.Save(ConfigurationSaveMode.Modified);