Response.Redirect cannot be called in a Page callback
Error Description
This error can occur when you use the HttpResponse.Redirect method to navigate to another page on a callback. A callback request expects a response from the same page and a redirect to another page causes the “Response.Redirect cannot be called in a Page callback” error.
Solution
Use the RedirectOnCallback(String) method to redirect a page to the specified URL when server-side processing is complete:
For v14.2 and earlier (BC2626):
string TARGET_URL = ...;
if(Page.IsCallback)
DevExpress.Web.ASPxWebControl.RedirectOnCallback(TARGET_URL);
else
Response.Redirect(TARGET_URL);
For v14.1 and older: