代码如下：
复制代码 代码如下:
public static string Config(string key)
{
ExeConfigurationFileMap file = new ExeConfigurationFileMap();
file.ExeConfigFilename = @"Providers\\Provider.config";
Configuration config = ConfigurationManager.OpenMappedExeConfiguration(file, ConfigurationUserLevel.None);
AppSettingsSection appsection = (AppSettingsSection)config.GetSection("appSettings");
return appsection.Settings[key].Value;
}

配置文件目录结构：
复制代码 代码如下:
<?xml version="1.0" encoding="utf-8" ?>
<configuration>
<appSettings>
<add key="ConnectionString" value="Server=(local);Database=DB;User Id=sa;Password=123" />
</appSettings>
</configuration>

调用：
复制代码 代码如下:
//里面的参数为配置文件的key
string strConn=Config("ConnectionString");