Get Windows Login and Logoff time in C# Windows application

label1.Text = WindowsIdentity.GetCurrent().Name.Split('\\')[1];
            label2.Text = WindowsIdentity.GetCurrent().Name.Split('\\')[0];
            string userName = WindowsIdentity.GetCurrent().Name.Split('\\')[1];
            string machineName = WindowsIdentity.GetCurrent().Name.Split('\\')[0];
            PrincipalContext c = new PrincipalContext(ContextType.Machine, machineName);
            //Specific User
            UserPrincipal uc = UserPrincipal.FindByIdentity(c, "Rashid");
            DateTime? LoggedInTime = uc.LastLogon;

            //Current LoggedIn User
            uc = UserPrincipal.FindByIdentity(c, userName);
            DateTime? CurrentUserLoggedInTime = uc.LastLogon;
            label3.Text = uc;

 This are my steps.