修該Config文件程序程式

using System;
using System.Collections.Generic;
using System.Text;
using System.Configuration;
using System.Xml;
using System.Reflection;

namespace Walter.K.Wang.Config
...{
    /**//// <summary>
    /// 讀寫配置文件操作類
    /// </summary>
    public class Config
    ...{
        /**//// <summary>
        /// 讀配置文件
        /// </summary>
        /// <param name="key">關鍵字</param>
        /// <returns>直</returns>
        public string ReadConfig(string key)
        ...{
            return ConfigurationManager.AppSettings[key].ToString();
        }

        /**//// <summary>
        ///  寫配置文件
        /// </summary>
        /// <param name="key">關鍵字</param>
        /// <param name="value">直</param>
        public void WriteConfig(string key,string value)
        ...{
            XmlDocument doc = new XmlDocument();
            //創建DLL文件
            doc.Load(Assembly.GetEntryAssembly().Location + ".config");
            //程序中片段碼
            XmlNode node = doc.SelectSingleNode("//appSettings");
            if (node == null)
                throw new InvalidOperationException("沒有找到AppSettings接點.");
            try
            ...{
                XmlElement elem = (XmlElement)node.SelectSingleNode(string.Format("//add[@key='{0}']", key));
                if (elem != null)
                ...{
                    elem.SetAttribute("value", value);
                }
                else
                ...{
                    elem = doc.CreateElement("add");
                    elem.SetAttribute("key", key);
                    elem.SetAttribute("value", value);
                    node.AppendChild(elem);
                }
                doc.Save(Assembly.GetEntryAssembly().Location + ".config");
            }
            catch(Exception Err)
            ...{
                throw new Exception(Err.Message);
            }
        }
    }
}