If you are not doing postbacks in a page or are always regenerating the controls on a page on each request, you should disable view state at the page level.
如果您不发回页，或者总是针对每个请求重新生成页上的控件，则应该在页级别禁用视图状态。
Why don't file uploads work during async postbacks?
为什么异步回送时不能使用文件上传？
Server events occur after postbacks, and they are handled in the server-side code that you write for the page.
伺服器事件会在回传后发生，并且会在为网页所撰写的伺服器端程序码中处理这些事件。
Server events occur after postbacks, and they are handled in the server-side code that you write for the page.
伺服器事件会在回传后发生，并且会在为网页所撰写的伺服器端程序码中处理这些事件。
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