System.Configuration.ConfigurationManager引用

使用appsettings的时候编译器提示说：警告   1 "System.Configuration.ConfigurationSettings.AppSettings"已过时:"This method is obsolete, it has been replaced by System.Configuration!System.Configuration.ConfigurationManager.AppSettings"

首先，添加对System.Configuration.dll 文件的引用；
其次，再将"System.Configuration.ConfigurationSettings.GetConfig替换为System.Configuration.ConfigurationManager.GetSection；
最后，将"System.Configuration.ConfigurationSettings.AppSettings"替换为System.Configuration.ConfigurationManager.AppSettings"。