Get Windows Login and Logoff time in C# Windows application

yeah i m in domain

this app is for domain

 UserPrincipal uc = UserPrincipal.FindByIdentity(c, "sohail");
after this step it is directly coming out and rest step are not executing
         
DateTime? LoggedInTime = uc.LastLogon;

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

Then you might have to provide domain name\User name

any other method to do so

Have you tried specifying the name of the Domain?

yeah i have put the domain name there