In an ASP.NET 4.0 web application, I have a user control that is wrapped by an UpdatePanel
<asp:UpdatePanel ID="UpdatePanel5" runat="server" UpdateMode="Conditional">
<UC:MyCustomCtrl ID="customCtrl" runat="server" />
I have an ASP.NET button in the user control that makes an asychronous request to the server
The server then creates an Excel spreadsheet and then places the spreadsheet in the HttpResponse to send back to the client's browser so they can open/save it.
However, it blows up at this point because the request to the server is asynchronous and apparently you can't put a binary in the HttpResponse during an asynchronous request.
How do I get around this?