AllowSubDirConfig参数的作用
appcmd设置虚拟路径属性时，有这么一个参数AllowSubDirConfig，是属性于类
VirtualDirectoryElementDefaults的
字面上看起来是是否允许对子目录进行设置，但我给目录的AllowSubDirConfig设为true和false时都可以对子目录运行设置
请问这个属性到底怎么用

[解决办法]
你理解错了，请参考文档http://learn.iis.net/page.aspx/150/understanding-sites-applications-and-virtual-directories-in-iis-70/

也就是说allowSubDirConfig控制你的web.config文件有效或者无效

By default, IIS uses configuration from Web.config files in the physical directory to which the virtual directory is mapped, as well as in any child directories in that physical directory. If you do not want to use Web.config files in child directories, specify false for the allowSubDirConfig attribute on the virtual directory.