Simple to replicate... Add an UpdatePanel to a new page and put an AsyncFileUpload in it with the "visible" property set to false. Also add a LinkButton and have the event "Click" set the AsyncFileUpload visibility to true. Uploads will no longer work with SaveAs under the "UploadedComplete" event for the AsyncFileUpload control.
Interestingly enough, this ONLY happens when visibility is set to false on the initial page loading. If you programatically set it to visible = false in the page_load event, the same error occurs. If you use something other than a LinkButton to trigger visible = true, the same bug occurs.
Comments: Thank you for sharing your experience!
Interestingly enough, this ONLY happens when visibility is set to false on the initial page loading. If you programatically set it to visible = false in the page_load event, the same error occurs. If you use something other than a LinkButton to trigger visible = true, the same bug occurs.
Comments: Thank you for sharing your experience!