我无法访问配置文件中的值.
Configuration config = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None);
var clientsFilePath = config.AppSettings.Settings["ClientsFilePath"].Value;
// the second line gets a NullReferenceException
.config file:
<?xml version="1.0" encoding="utf-8" ?>
<configuration>
<appSettings>
<!-- ... -->
<add key="ClientsFilePath" value="filepath"/>
<!-- ... -->
</appSettings>
</configuration>
你有什么建议吗？我该怎么办？