This is just some strange behavior I have observed on a user's machine. During testing, and most of the time in production, the upload control has been working fine, but I am running into a problem. I will preface this by saying that I have only seen this problem occur with a user running IE7, and that I don't know what their security settings are because the client has everyone's setting locked by group policy.
The problem is this:
The user browses for a file, selects one, and the file is uploaded immediately. Everything fine there, but then they click on any other control on the page and the upload control immediately begins uploading again. Often, it seems, this second upload fails. At the very least it is very time consuming and irritating for the users, since this second upload "cancels" the server request for the control they actually clicked on.
The AsyncUploadControl is not inside of any update panels, although there are several in use on the page. I've even seen this behavior when a user expands a DropDownList control with its "AutoPostback" property set to true.
I have gotten reports from several users at this client (this client accounts for 2/3 of the people using the system) that they are having problems uploading files, but I can't confirm that it's all the same problem.
I've done several searches on the web, but I have been unable to find anything specfically referencing this problem, so any help anyone could offer would be greatly appreciated.
Thanks!
Please test uploading file into this site From IE7 and click somewhere on the page the uploader will reload the file
http://www.asp.net/ajax/ajaxcontroltoolkit/Samples/AsyncFileUpload/AsyncFileUpload.aspx