原文:C# 不重启程序修改并保存配置文件（appSettings节点）
private static void UpdateAppConfig(string newKey, string newValue)
{
bool isModified = false;
foreach (string key in ConfigurationManager.AppSettings)
{
if (key == newKey)
{
isModified = true;
}
}
Configuration config = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None);
if (isModified)
{
config.AppSettings.Settings.Remove(newKey);
}
config.AppSettings.Settings.Add(newKey, newValue);
config.Save(ConfigurationSaveMode.Modified);
ConfigurationManager.RefreshSection("appSettings");
}
之后直接用ConfigurationManager.AppSettings[key]读取就行了。