To get the current logged in user at the system I use this code:
string opl = System.Security.Principal.WindowsIdentity.GetCurrent().Name.ToString();
I work on an ASP.NET application where I need this information. So I've put my application on a server and tried the code above, and I get "Network Service" in the string opl. I need to know the current user of the PC who accesses my ASP.NET application.
The quick answer is User = System.Web.HttpContext.Current.User
Ensure your web.config has the following authentication element.
<configuration>
<system.web>
<authentication mode="Windows" />
<authorization>
<deny users="?"/>
</authorization>
</system.web>
</configuration>
Further Reading: Recipe: Enabling Windows Authentication within an Intranet ASP.NET Web application