Empty file in file upload control

I am using AsyncFileUpload of ajax toolkit of asp.net. But while uploading a file of size 0kb, it gives me error "Unhandled exception: the file attached is empty".

开发者_如何学GoIs there any solution for uploading a blank file.

Is your AsyncFileUpload control located inside an UpdatePanel? There is some browser security feature that wont allow a file to be posted from within an UpdatePanel.

If you could attach an example of your code I could be more helpful.