C#操作XML配置文件

 1          /// <summary>
 2         /// 根据Key取Value值
 3         /// </summary>
 4         /// <param name="key"></param>
           命名空间：

using System.Configuration;
using System.Web;

 5         public static string GetValue(string key)
 6         {
 7             return ConfigurationManager.AppSettings[key].ToString().Trim();
 8         }
 9         /// <summary>
10         /// 根据Key修改Value
11         /// </summary>
12         /// <param name="key">要修改的Key</param>
13         /// <param name="value">要修改为的值</param>
14         public static void SetValue(string key, string value)
15         {
16             System.Xml.XmlDocument xDoc = new System.Xml.XmlDocument();
17             xDoc.Load(HttpContext.Current.Server.MapPath("~/Configs/system.config"));
18             System.Xml.XmlNode xNode;
19             System.Xml.XmlElement xElem1;
20             System.Xml.XmlElement xElem2;
21             xNode = xDoc.SelectSingleNode("//appSettings");
22 
23             xElem1 = (System.Xml.XmlElement)xNode.SelectSingleNode("//add[@key='" + key + "']");
24             if (xElem1 != null) xElem1.SetAttribute("value", value);
25             else
26             {
27                 xElem2 = xDoc.CreateElement("add");
28                 xElem2.SetAttribute("key", key);
29                 xElem2.SetAttribute("value", value);
30                 xNode.AppendChild(xElem2);
31             }
32             xDoc.Save(HttpContext.Current.Server.MapPath("~/Configs/system.config"));
33         }