绕过应用程序池中的服务ID以确定用户ASP.NET C的实际用户名

I have a website that uses an app pool with a service ID to connect to a database. I want to be able to populate a textbox on the web page that shows their actual windows log in name and not the service ID that is associated with the app pool. I want this so I can use this information to do some filtering on a gridview that shows some data from the database based on their username. Currently I have tried a couple different ways.I have a website that uses an app pool with a s