上传控件：安装上传控件后，上传视频速度更快、更稳定。上传超大文件不用担心网页瞬断造成发布失败，系统会自动保存上传进度，下次还可继续上传。
允许选择有点可能，当用户选择部分真实上传控件的值时，我们选择整个伪造控件的值。
Allowing selection is somewhat possible. When the user selects any part of the real file upload, we select the entire value of the fake file upload.
很难找到一个像样的文件上传控件，能够上传大文件，显示当前进度并且能在浏览器的安全级别设置为中级的环境运行。
It is difficult to find a decent upload control that handles large files, shows a progress bar, and still works in a medium-trust hosting environment.
在ASP.NET使用上传控件的第一步：在WebForm里添加这个服务器控件（查看 UploadPage/Default.aspx），然后设置控件的属性。
The first step in using it in ASP.NET is to add the server control to a Web form (see UploadPage/Default.aspx) and setting the upload page in the server control's properties.
应用推荐