Rushi ,
After the files be uploaded , the uploader will fire a javascript OnPostback event , and then
post back the form
So the page will refresh , or the content will refresh if you using MS-Ajax .
If you do not want the modal popup UI be refreshed , you need handle the OnPostback event.
if the OnPostback handler return false , the uploader will stop posting the form.
But you also can't let server side FileUploaded event be executed.
In OnPostback event , you can also get the uploader's guid list and handle it.
Please check the MVC samples code .
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Another easy way : maybe you can call the ModalPopup1.Show(); in the FileUploaded event to keep the layer open.
Regards,
Terry