Balloon tip text must have a non-empty value exception

I got "Balloon tip text must have a non-empty value" exception when the OnStateChange(). This method called when my application is minimized.

 void OnStateChanged(object sender, EventArgs args)
    {
        try
        {
            if (WindowState == WindowState.Minimized)
            {
                Hide();
                if (TippuTrayNotify != null)
                {
                    TippuTrayNotify.Visible = true;
                    TippuTrayNotify.ShowBalloonTip(2000);
                }
            }
            else
                m_storedWindowState = WindowState;
        }catch(Exception ex){
            SystemLog.WriteLine("(Error) OnStateChange : "+ex.Message+" ;");
        }
    }

I initial TippuTrayNotify within MainWindow constructor

     public MainWindow()
    {
        InitializeComponent();
         TippuTrayNotify = new System.Windows.Forms.NotifyIcon(); 
            TippuTrayNotify.Icon = new System.Drawing.Icon("Icons/i开发者_如何学编程con_64.ico");

            TippuTrayNotify.BalloonTipTitle = "OlivInClass";
            TippuTrayNotify.Text = "OlivInClass";
            TippuTrayNotify.DoubleClick += new EventHandler(TippuTrayNotify_DoubleClick);
    }

Any solution please

Text appears to be what shows when you mouse over the icon, not the balloon tip text. That's set via the BalloonTipText property.

notifyIcon1.BalloonTipIcon = ToolTipIcon.Info;
notifyIcon1.BalloonTipText = "your text";
notifyIcon1.BalloonTipTitle = "Welcome Message";
notifyIcon1.ShowBalloonTip(1000);