The server-side events are not raised when UploadBox is placed inside a GridView even when GridView is inside UpdatePanel. The following solution explains you how to trigger UploadBox server-side events when UploadBox is wrapped inside Grid.
When the UploadBox is under the following tags; ItemTemplate, UpdatePanel and ContentTemplate, you can trigger the server-side events for Uploadbox using PostBackTrigger. You can refer the following code example.
|Article ID:||Published Date:||Last Revised Date:||Platform:||Control:|
|2599||09/10/2014||12/04/2014||ASP.NET Web Forms (Classic)||UploadBox|