Gets the page that transferred control to the current page.
Assembly: System.Web (in System.Web.dll)
The current user is not allowed to access the previous page.
ASP.NET routing is in use and the previous page's URL is a routed URL. When ASP.NET checks access permissions, it assumes that the URL is an actual path to a file. Because this is not the case with a routed URL, the check fails.
When you use the Transfer method or use cross-page posting to transfer processing from one ASP.NET page to another, the originating page contains request information that might be required for the destination page. You can use the property to access that information.
If the current page is being rendered as a result of a direct request (not a transfer or cross-post from another page), theproperty contains null.
Available since 2.0