windows 7 下创建FileStream 时出现 UnauthorizedAccessException

lakers009

　　[Issue]windows 7 下创建FileStream 时出现 UnauthorizedAccessException
　　
　　[Resolution]
　　之前曾使用在其他盘创建一个文件夹，文件夹的security允许everyone来进行Full control，然后把文件创建在这个文件夹下面，即使是这样也仍然会出现UnauthorizedAccessException。
　　最后的解决方案是把文件创建在ApplicationData下面就不会出现UnauthorizedAccessException。
　　StringBuilder folder = new StringBuilder(Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData));
　　
　　在stackoverflow网站上查了下UnauthorizedAccessException应该改是操作系统抛出来的异常，这样说来，win7 或者vista只能在ApplicationData下面创建用户自己的文件。
　　

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A UnauthorizedAccessException is thrown when there is a permissions error accessing the file on disk. That is an error at the operating system level such as a normal user trying to overwrite an operating system file (like kernel32.dll). 　　A SecurityException is thrown if there is a security violation at the CLR level. For example if you are running as a low access ClickOnce application and attempt to read / write to a place in the file system forbidden by the CLR security settings in the process.