Tuesday, 9 November 2010

"the file attached is invalid" error using asyncfileupload

I recently dabbled with the neat control AsyncFileUpload from the Ajax Control ToolKit which facilitates the asynchronous upload of files via the browser to the server without affecting the rest of the parent page and without causing a full postback.

I did however get an error "the file attached is invalid" when first trying it out.

Eventually fixed by adding the following to the design code: