Windows Username

To get information about the current user context, use one of the following:

Environment.UserName

Only the username of the calling user (Run As would get this user)

System.Security.Principal.WindowsIdentity.GetCurrent().Name

Gets the Domain and the user <Domain>\<Username>

System.Security.Principal.WindowsIdentity.GetCurrent().User

Gets the SID of the user e.g. “S-1-5-21-992878714-4041223874-2616370337-1001”

These calls are at least valid for applications like WPF, WinForms and Console Applications.