C# – Display progress bar in the program’s task bar icon

For below .NET 4, or WinForms in any .NET version

Using the Windows API Code Pack from Microsoft (as Keeron mentioned), it's really simple. You just need to use the TaskbarManager. E.g.

To start the progress:

TaskbarManager.Instance.SetProgressState(TaskbarProgressBarState.Normal);

To update the progress:

TaskbarManager.Instance.SetProgressValue(currentValue, maxProgressValue);

And when when you're done, to end the progress:

TaskbarManager.Instance.SetProgressState(TaskbarProgressBarState.NoProgress);

There is more you can do, but that should get you started and might be all you need.

For .NET 4 and above with WPF

You can use System.Windows.Shell.TaskbarItemInfo. E.g. in the Xaml for your main window, you'll need to add:

<Window.TaskbarItemInfo>
    <TaskbarItemInfo x:Name="taskBarItemInfo" />
</Window.TaskbarItemInfo>

Then to update the progress, you would do something like:

taskBarItemInfo.ProgressState = TaskbarItemProgressState.Normal;

for (int i = 0; i < 100; i++)
{
    taskBarItemInfo.ProgressValue = i / 100.0;
    Thread.Sleep(50); // whatever the 'work' really is
}

taskBarItemInfo.ProgressState = TaskbarItemProgressState.None;

Don't forget that if you're doing the 'work' on a background thread (which is probably a good idea for long running tasks), you will need to switch back to the UI thread to update the taskbar.

I just wanted to add some taskbar progress animation to my WinForms application, without having to download code packs or switch to WPF to use TaskbarItemInfo.

The solution was a class that uses the ITaskbarList3 interface:

using System;
using System.Runtime.InteropServices;

public static class TaskbarProgress
{
    public enum TaskbarStates
    {
        NoProgress    = 0,
        Indeterminate = 0x1,
        Normal        = 0x2,
        Error         = 0x4,
        Paused        = 0x8
    }

    [ComImport()]
    [Guid("ea1afb91-9e28-4b86-90e9-9e9f8a5eefaf")]
    [InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
    private interface ITaskbarList3
    {
        // ITaskbarList
        [PreserveSig]
        void HrInit();
        [PreserveSig]
        void AddTab(IntPtr hwnd);
        [PreserveSig]
        void DeleteTab(IntPtr hwnd);
        [PreserveSig]
        void ActivateTab(IntPtr hwnd);
        [PreserveSig]
        void SetActiveAlt(IntPtr hwnd);

        // ITaskbarList2
        [PreserveSig]
        void MarkFullscreenWindow(IntPtr hwnd, [MarshalAs(UnmanagedType.Bool)] bool fFullscreen);

        // ITaskbarList3
        [PreserveSig]
        void SetProgressValue(IntPtr hwnd, UInt64 ullCompleted, UInt64 ullTotal);
        [PreserveSig]
        void SetProgressState(IntPtr hwnd, TaskbarStates state);
    }

    [ComImport()]    
    [Guid("56fdf344-fd6d-11d0-958a-006097c9a090")]
    [ClassInterface(ClassInterfaceType.None)]
    private class TaskbarInstance
    {
    }

    private static ITaskbarList3 taskbarInstance = (ITaskbarList3)new TaskbarInstance();
    private static bool taskbarSupported = Environment.OSVersion.Version >= new Version(6, 1);

    public static void SetState(IntPtr windowHandle, TaskbarStates taskbarState)
    {
        if (taskbarSupported) taskbarInstance.SetProgressState(windowHandle, taskbarState);
    }

    public static void SetValue(IntPtr windowHandle, double progressValue, double progressMax)
    {
        if (taskbarSupported) taskbarInstance.SetProgressValue(windowHandle, (ulong)progressValue, (ulong)progressMax);
    }
}

Example of how easy it is to use:

TaskbarProgress.SetState(this.Handle, TaskbarProgress.TaskbarStates.Indeterminate);

or

TaskbarProgress.SetValue(this.Handle, 50, 100);
TaskbarProgress.SetState(this.Handle, TaskbarProgress.TaskbarStates.Error);