说明：  在 Vista 和Windows 7 系统中默认是不自带 UserAccounts.CommonDialog 组件的。那么如何在 Windows 7 系统中向用户显示一个用来选择文件的对话框呢？答案是 html 中的文件选择对话框。
(Vista and Windows 7 system default is not own UserAccounts.CommonDialog components. So how Windows 7 system to the user to display a file dialog box is used to select it? The answer is that html file selection dialog.)