winfrom 读取config文件的问题

< appSettings >
< clear />
< add key = "userName "value = "" />
< add key = "password "value = "" />
< add key = "Department "value = "" />
< add key = "returnValue "value = "" />
< add key = "pwdPattern "value = "" />
< add key = "userPattern "value = "" />
</ appSettings >

我需要把所有的key和对用的 value读出来

 foreach (var item in System.Configuration.ConfigurationSettings.AppSettings)
{
...
}