这是一个有两个假设的一般解决方案。首先，UserId不是UILabel。其次，你打算使用在第二行实例化的 view ，而不是使用 secondViewController

Here's a general solution with two assumptions. First, UserId is not a UILabel. Second, you meant to use view which was instantiated in the second line, instead of using secondViewController

override func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
    var view: Dashboard = self.storyboard?.instantiateViewControllerWithIdentifier("Dashboard") as Dashboard

    self.navigationController?.pushViewController(view, animated: true)
    view.UserId = employeesId[indexPath.row]
}

这是Dashboard的样子：

Here's what Dashboard looks like:

class Dashboard: UIViewController {
    var UserId: String!
    @IBOutlet var userIDLabel: UILabel!

    override func viewDidLoad() {
        super.viewDidLoad()

        // Do any additional setup after loading the view.
        userIDLabel.text = UserId
    }

    ...
}