在类之间共享对象

Question

I have a program written in c# that contains a listbox with an observable collection. I want a balloon to pop-up for the user (in the system tray) when the collection has an item added. I have a class that contains a method for notifying the listbox when an item is added (see below):

 void OnFileCreated(object sender, FileSystemEventArgs e)
    {
        if (!base.Dispatcher.CheckAccess())
        {
            base.Dispatcher.BeginInvoke(
                DispatcherPriority.Normal,
                (FileSystemEventHandler)OnFileCreated,
                sender, e);
        }
        else
        {
            // Ignore new directories.
            if (File.Exists(e.FullPath))
            {
                Debug.WriteLine("File Created: " + e.FullPath);

                _files.Add(new ObservableFileInfo(e.FullPath));

                //Alert users to new request
                string title = "Access Request";
                string text = "A new access request has been submitted";


                //show balloon with built-in icon
                tbi.ShowBalloonTip(title, text, BalloonIcon.Error);                  


            }
        }
    }

The code works exactly as intended apart from the fact that the balloon will only show if I create a new instance of the balloon within the OnFileCreated method (not seen above as I took the code out). For reference, I am using the system tray icon .dll from the following project: http://www.codeproject.com/Articles/36468/WPF-NotifyIcon?fid=1540774&select=4624878&fr=51#xx0xx

My issue is that I already have a system tray icon initiated in the MainWindow class, but I cannot call on it to show a balloon from my OnFileCreated method. I am not sure how I can "share" this information across classes.

If anyone has any ideas that would be great.

Answer 1

I ended up using FindResource to locate the resource defined in the xaml resource document. This was specified in the project code I was referencing to, however FindResource was not working by itself, I needed to add App.Current:

notifyIcon = (TaskbarIcon)App.Current.FindResource("NotifyIcon");
notifyIcon.ShowBalloonTip(title, text, BalloonIcon.Error);