C# – Developing a simple Windows system tray desktop app to consume a .NET web service

In terms of language support, you can do it in C++, Java, C#, Python, etc. In practical terms, I'd say C++, Java and C# are the choice for most of the users. But keep in mind that GUI support in both C++ and Java is complex to learn and use. If you plan to make many large projects, performance is a concern (both in size and speed) and you need a simple installation process, use C++. If these last restrictions don't apply (only the size and number of projects), use Java. Assume you'll have to spend some considerable initial time preparing the infrastructure (libraries & etc.).

If your plan is more short-term (not so many projects, not so large ones), use C#. It's realy the easiest to learn, use and produce code that works, and with the Mono project it's not restricted to MS platforms anymore.

The code project article Creating a Tasktray Application gives a very simple explanation and example of creating an application that only ever exists in the System Tray.

Basically change the Application.Run(new Form1()); line in Program.cs to instead start up a class that inherits from ApplicationContext, and have the constructor for that class initialize a NotifyIcon

static class Program
{
    /// <summary>
    /// The main entry point for the application.
    /// </summary>
    [STAThread]
    static void Main()
    {
        Application.EnableVisualStyles();
        Application.SetCompatibleTextRenderingDefault(false);

        Application.Run(new MyCustomApplicationContext());
    }
}


public class MyCustomApplicationContext : ApplicationContext
{
    private NotifyIcon trayIcon;

    public MyCustomApplicationContext ()
    {
        // Initialize Tray Icon
        trayIcon = new NotifyIcon()
        {
            Icon = Resources.AppIcon,
            ContextMenu = new ContextMenu(new MenuItem[] {
                new MenuItem("Exit", Exit)
            }),
            Visible = true
        };
    }

    void Exit(object sender, EventArgs e)
    {
        // Hide tray icon, otherwise it will remain shown until user mouses over it
        trayIcon.Visible = false;

        Application.Exit();
    }
}