Change taskbar icon at runtime on deployed app

Question

I would like to change taskbar icon to notify the user when a new message is received like outlook when you receive a new mail.

I already search solution on web and it's all about changing the window icon like this:

Uri iconUri = new Uri("Resources/envelop.ico", UriKind.Relative);
this.Icon = BitmapFrame.Create(iconUri);

It's working well on Visual Studio but I found out that it's not changing my task bar on deployed app because it's a read-only variable. And worse it's change only the top-left attached icon that I didn't want to change anyways.

So is there a way to do it? Outlook did it and Chrome too so there must be a way.

UPDATE

To force the icon refresh on my deployed app I have to pin/unpin my icon taskbar, unfortunately this is a user command only so I can't do this in wpf programmatically without exploiting some dirty manners which would be too unstable.

Actually I'm trying to find a way to refresh Icon cache without doing it for each Windows OS or version.

Answer 1

Here is a small working demo doing the job !

Add Icons:

Chose 2 Icons (for example Outlook Standard & Outlook MailReceived):

Add this to the code behind of your MainWindow

public partial class MainWindow : Window
{
    private int _imgId;

    public MainWindow()
    {
        InitializeComponent();
        this.Loaded += MainWindow_Loaded;
    }

    private void MainWindow_Loaded(object sender, RoutedEventArgs e)
    {
        //Start timer to periodically change the App Icon:
        new System.Threading.Thread(() =>
        {
            System.Timers.Timer timer = new System.Timers.Timer();
            timer.Interval = 100;
            timer.AutoReset = true;
            timer.Elapsed += Timer_Elapsed;
            timer.Start();
        }).Start();
    }

    private void Timer_Elapsed(object sender, System.Timers.ElapsedEventArgs e)
    {
        try
        {      
            //Change AppIcon on UI-Thread         
            Dispatcher.Invoke(() =>
            {
                /* CHANGE YOUR ICONS HERE !!! */
                BitmapSource ms_icon = System.Windows.Interop.Imaging.CreateBitmapSourceFromHIcon(Properties.Resources.Microsoft_logo.Handle, Int32Rect.Empty, BitmapSizeOptions.FromEmptyOptions());
                BitmapSource so_icon = System.Windows.Interop.Imaging.CreateBitmapSourceFromHIcon(Properties.Resources.images.Handle, Int32Rect.Empty, BitmapSizeOptions.FromEmptyOptions());
                if (_imgId == 0)
                {
                    this.Icon = so_icon;
                    _imgId = 1;
                }
                else
                {
                    this.Icon = ms_icon;
                    _imgId = 0;
                }
            });
        }
        catch (Exception ex)
        {
            System.Diagnostics.Trace.WriteLine(ex.Message);               
        }            
    }
}

Will produce this output (switch every 100ms):

Answer 2

Two Steps you need to consider:

1. You need to pay attention if your software is also installed in Control Panel. If it does, then try to uninstall it from there but keep your runtime folder of your software somewhere to keep them for a test.

2. Delete from %AppData% your software data files and try to run software again without installing it (Where you copied your runtime folder) and you should be able to see how Taskbar is refreshing it.

One thing you need to sort out is why having software installed in Control panel makes such glitch that it doesn't refresh your icon in taskbar.

Answer 3

For me this solution was working.

Created this with code from Write text on bitmap in C#

    private Icon DrawIcon(Brush brush)
    {
        //https://stackoverflow.com/questions/6311545/c-sharp-write-text-on-bitmap     
        Bitmap bmp = new Bitmap(MyNameSpace.Properties.Resources.desktop_windows_48px);

        // Create a rectangle for the entire bitmap
        RectangleF rectf = new RectangleF(0, 0, bmp.Width, bmp.Height);

        // Create graphic object that will draw onto the bitmap
        Graphics g = Graphics.FromImage(bmp);

        // The smoothing mode specifies whether lines, curves, and the edges of filled areas use smoothing (also called antialiasing). One exception is that path gradient brushes do not obey the smoothing mode. Areas filled using a PathGradientBrush are rendered the same way (aliased) regardless of the SmoothingMode property.
        g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.AntiAlias;

        // The interpolation mode determines how intermediate values between two endpoints are calculated.
        g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic;

        // Use this property to specify either higher quality, slower rendering, or lower quality, faster rendering of the contents of this Graphics object.
        g.PixelOffsetMode = System.Drawing.Drawing2D.PixelOffsetMode.HighQuality;

        // This one is important
        g.TextRenderingHint = System.Drawing.Text.TextRenderingHint.AntiAliasGridFit;

        // Draw the text onto the image
        g.FillRectangle(brush, new Rectangle(2, 4, 20, 12));

        // Flush all graphics changes to the bitmap
        g.Flush();

        Bitmap temp = bmp;

        // Get an Hicon for myBitmap.
        IntPtr Hicon = temp.GetHicon();

        // Create a new icon from the handle.
        Icon newIcon = Icon.FromHandle(Hicon);

        return newIcon;            
    }

I am also using a NotifyIcon but that does not change alot for you.

_notifyIcon.Icon = DrawIcon(Brushes.Blue);
MainWindow.Icon =  Imaging.CreateBitmapSourceFromHIcon(_notifyIcon.Icon.Handle, Int32Rect.Empty, BitmapSizeOptions.FromEmptyOptions());

Lateron I change it like this (might be similar when just changing the icon source.

    private void App_StateChanged(object sender, StateChangedEventArgs e)
    {
        if(e.State == ApplicationState.Defective)
        {
            //Show window on error !
            ShowMainWindow();
            //(sender as Window).Activate();
        }
        _notifyIcon.Icon = DrawIcon(e.StateBrush);
        MainWindow.Icon = Imaging.CreateBitmapSourceFromHIcon(_notifyIcon.Icon.Handle, Int32Rect.Empty, BitmapSizeOptions.FromEmptyOptions());
        _notifyIcon.Visible = true;
    }

It looks similar to this:

Default:

On Error:

Hope this is helpful !