c# – 无法将自定义配置部分保存到app.config

Configuration configuration =     ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None);

            //Read the TunnelSection from the configuration file
            TunnelSection tunnels = ConfigurationManager.GetSection("TunnelSection") as TunnelSection;


            HostConfigElement newhost = new HostConfigElement();

            newhost.Password = "hola";
            newhost.SSHPort = 22;
            newhost.SSHServerHostname = "holahola";

            TunnelConfigElement newtunnel = new TunnelConfigElement();

            newtunnel.LocalPort = 12;
            newtunnel.RemotePort = 12;
            newtunnel.Name = "12";
            newtunnel.DestinationServer = "12";

            TunnelCollection newtunnelcollection = new TunnelCollection();

            newtunnelcollection.Add(newtunnel);

            newhost.Tunnels = newtunnelcollection;

            tunnels.Tunnels.Add(newhost);             

            ConfigurationManager.RefreshSection("TunnelSection");

            configuration.Save(ConfigurationSaveMode.Full);

问题是配置文件未被修改.如果我遍历TunnelSection,我会看到已添加新主机.

为了排除权限问题,我尝试将设置添加到appsettings,如下所示：

configuration.AppSettings.Settings.Add("hola","hola");

这很好用.

我也试过saveas但无济于事.

有任何想法吗？
TIA