Config操作类

using System;
using System.Configuration;

public sealed class Config
    {
        #region appSettings节点
        /// <summary>
        /// 获取配置文件指定的值
        /// </summary>
        /// <param name="key">健</param>
        /// <param name="defaultvalue">值为Null时返回的默认值</param>
        /// <returns>健对应的值，如果为Null返回默认值</returns>
        public static string GetConfig(string key, string defaultvalue)
        {
            string _value = GetConfig(key);
            return string.IsNullOrEmpty(_value) ? defaultvalue : _value;
        }
        /// <summary>
        /// 获取配置文件指定的值
        /// </summary>
        /// <param name="key">健</param>
        /// <returns>健对应的值</returns>
        public static string GetConfig(string key)
        {
            return string.IsNullOrEmpty(ConfigurationManager.AppSettings[key]) ? string.Empty : ConfigurationManager.AppSettings[key];
        }
        /// <summary>
        /// appSettings节点下是否存在某健
        /// </summary>
        /// <param name="key"></param>
        /// <returns></returns>
        public static bool IsExistKey(string key)
        {
            return !string.IsNullOrEmpty(key) && ConfigurationManager.AppSettings[key] != null;
        }
        /// <summary>
        ///　对appSettings节点添加健值
        ///　如果健已经存在则更改值
        ///　添加后重新保存
        /// </summary>
        /// <param name="key">添加的健</param>
        /// <param name="key">添加的值</param>
        public static void AddConfig(string key, string value)
        {
            if (string.IsNullOrEmpty(key)) return;
            Configuration configuration = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None);
            if (IsExistKey(key))
                configuration.AppSettings.Settings[key].Value = value;
            else
                configuration.AppSettings.Settings.Add(key, value);
            try
            {
                configuration.Save();
            }
            catch (Exception)
            {
                throw;
            }
            ConfigurationManager.RefreshSection("appSettings");
        }
        #endregion
        #region connectionStrings节点
        /// <summary>
        /// ConnectionStrings.Count
        /// </summary>
        /// <returns></returns>
        public static int GetConnsCount
        {
            get { return ConfigurationManager.ConnectionStrings.Count; }
        }
        /// <summary>
        /// 读取数据库配置文件(connectionStrings节点)
        /// </summary>
        /// <param name="key">健名</param>
        /// <returns></returns>
        public static string GetConfigConn(string key)
        {
            return !string.IsNullOrEmpty(key) && ConfigurationManager.ConnectionStrings[key] != null ? ConfigurationManager.ConnectionStrings[key].ConnectionString : string.Empty;
        }
        /// <summary>
        /// 健不存在或值为Null
        /// </summary>
        /// <param name="key">健名</param>
        /// <returns></returns>
        public static bool GetConfigConnIsNull(string key)
        {
            return string.IsNullOrEmpty(key) || ConfigurationManager.ConnectionStrings[key] == null || string.IsNullOrEmpty(ConfigurationManager.ConnectionStrings[key].ConnectionString);
        }
        /// <summary>
        /// 保存配置数据库连接字符串 
        /// 如果不存在连接字符串，则创建并设置字符串
        /// </summary>
        /// <param name="key">要操作的节点</param>
        /// <param name="value">值</param>
        public static void SaveConfigConn(string key, string value)
        {
            if (string.IsNullOrEmpty(key)) return;
            Configuration configuration = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None);
            if (configuration.ConnectionStrings.ConnectionStrings[key] == null)
                configuration.ConnectionStrings.ConnectionStrings.Add(new ConnectionStringSettings(key, value));
            else
            {
                foreach (ConnectionStringSettings conn in configuration.ConnectionStrings.ConnectionStrings)
                {
                    if (conn.Name != key||conn.ConnectionString==value) continue;
                    conn.ConnectionString = value;
                    break;
                }
            }
            try
            {
                configuration.Save();
            }
            catch (Exception)
            {
                throw;
            }
            ConfigurationManager.RefreshSection("connectionStrings");
        }
        #endregion
    }