AppConfig 操作简易封装

private static string _PortName;

public static string PortName
{
    get
    {
        //如果配置信息已读到内存则下次不需要再从文件中读了，修改配置也只需要修改内存中的值
        if (!string.IsNullOrEmpty(_PortName))
            return _PortName;
        try
        {
            _PortName = ConfigurationManager.AppSettings["PortName"].ToString();
            return _PortName;
        }
        catch (Exception ex)
        {
            throw ex;
        }
    }
    set
    {
        //更新缓存，下次直接读缓存
        _PortName = value;
        //持久化到文件
        SetConfig("PortName", value);
    }
}

public static void SetConfig(string key, string value)
{
    try
    {
        Configuration config = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None);
        if (config.AppSettings.Settings[key] != null)
            config.AppSettings.Settings[key].Value = value;
        else
            config.AppSettings.Settings.Add(key, value);

        config.Save(ConfigurationSaveMode.Modified);

        //刷新节点，这样下次检索时将从磁盘重新读取它
        ConfigurationManager.RefreshSection("appSettings");
    }
    catch (Exception ex)
    {
        throw ex;
    }
}