SPSecurity.CatchAccessDeniedException property
Gets or sets a value indicating whether "access denied" exceptions within page requests are caught and handled by Microsoft SharePoint Foundation 2010.
Assembly: Microsoft.SharePoint (in Microsoft.SharePoint.dll)
Property value
Type: System.Booleantrue if the exceptions are handled by Microsoft SharePoint Foundation 2010; otherwise, false. The default is true.
If set to true, access denied exceptions inside page requests are explicitly handled by the platform. For example, when Forms-based authentication is used, anonymous users are redirected to the login page. If the user is already authenticated, he may be redirected to an error message page such as _layouts/AccessDenied.aspx.
If you want to handle access denied exceptions with your own code, you should save the original value in a variable. Set CatchAccessDeniedException to false just before the beginning of your try block. At the end of your code, restore the original value in a finally block, so that other pieces in the system still behave the same way.