Windows 7 Taskbar C# Quick Reference

March 9, 2010

Following are some listings to be used as a quick reference to common Windows 7 Taskbar features using Windows API Code Pack.

The code in this post is based on previous work by Yochay and Sasha.


Setting the process Application ID

TaskbarManager.Instance.ApplicationId = “TaskbarManaged”;

Note: This should be done before the window is shown, a good place is on form load.

Setting the Application ID of a window

TaskbarManager.Instance.SetApplicationIdForSpecificWindow(form.Handle, “SomethingElse”);

or in WPF:

TaskbarManager.Instance.SetApplicationIdForSpecificWindow(wpfWindow, “SomethingElse”);

Adding a file into the Recent category on the JumpList

 _jumpList = JumpList.CreateJumpList();



Note: You must register (associate) the file type with your application for this to work.
Note 2: If you use the common dialogs to open a file it will get added automatically to the recent list.

Adding tasks to the JumpList

IJumpListTask task1 = new JumpListLink(filePath, taskTitle)
    Arguments = arguments,
    WorkingDirectory = workingDirectory

IJumpListTask separator = new JumpListSeparator();
IJumpListTask task2 = …

_jumpList.AddUserTasks(task1, separator, task2);

Adding custom categories

JumpListCustomCategory category = new JumpListCustomCategory(“My Category”);

IJumpListItem item1 = new JumpListLink(path1, title1);
IJumpListItem item2 = new JumpListLink(path2, title2);

category.AddJumpListItems(item1, item2);

Creating Thumbnail Toolbars


ThumbnailToolbarButton button1 = new ThumbnailToolbarButton(icon, tooltip);
button1.Click += delegate
    MessageBox.Show(“button1 clicked”);

TaskbarManager.Instance.ThumbnailToolbars.AddButtons(form.Handle, button1);


Setting Overlay Icon

TaskbarManager.Instance.SetOverlayIcon(icon, accessibilityText);

Setting Progress State and Value

TaskbarManager.Instance.SetProgressState(TaskbarProgressBarState.Normal, form.Handle);
TaskbarManager.Instance.SetProgressValue(currentValue, maximumValue, form.Handle);

Customizing Live Thumbnail

TabbedThumbnail preview = new TabbedThumbnail(parentForm.Handle, childForm.Handle);
preview.TabbedThumbnailBitmapRequested += (o, e) =>
        Bitmap bmp = new Bitmap(width, height);
        // draw custom bitmap…
        e.Handled = true;

Extra Notes

A drawback in Windows API Code Pack v1.0.1

When using the Windows API Code Pack library to add Taskbar features to your WinForms application you must add a references to the following WPF DLLs: PresentationCore.dll, PresentationFramework and WindowsBase.dll

The reason is that every Taskbar function in the library that has an handle in its arguments comes in pair, the first expects a native IntPtr (used with myWinForm.Handle property) and the second expects a WPF Window object. Since we use a class that expects WPF types in its arguments (Taskbar) we must add the WPF DLLs to our WinForms project.

A Bug in Windows API Code Pack v1.0.1

ThumbnailToolbarButton Click event isn’t fired when process is running elevated (i.e. as Administrator)

The problem is that some of the taskbar messages doesn’t pass thru the Windows UIPI mechanism.
A quick fix is to add the following line to the load event:


private void Form_Load(object sender, EventArgs eventargs)


The definition of this method is brought here:

#region Fix bug in Windows API Code Pack

[DllImport(“user32.dll”, EntryPoint = “RegisterWindowMessage”, SetLastError = true, CharSet = CharSet.Unicode)]
private static extern uint RegisterWindowMessage([MarshalAs(UnmanagedType.LPWStr)] string lpString);

[DllImport(“user32.dll”, SetLastError = true)]
private static extern IntPtr ChangeWindowMessageFilter(uint message, uint dwFlag);

private const uint MSGFLT_ADD = 1;
private const uint WM_COMMAND = 0x0111;
private const uint WM_SYSCOMMAND = 0x112;
private const uint WM_ACTIVATE = 0x0006;

/// <summary>
/// Specifies that the taskbar-related windows messages should
/// pass through the Windows UIPI mechanism even if the process is
/// running elevated. Calling this method is not required unless the
/// process is running elevated.
/// </summary>
private static void AllowTaskbarWindowMessagesThroughUIPI()
    uint WM_TaskbarButtonCreated = RegisterWindowMessage(“TaskbarButtonCreated”);

    ChangeWindowMessageFilter(WM_TaskbarButtonCreated, MSGFLT_ADD);
    ChangeWindowMessageFilter(WM_COMMAND, MSGFLT_ADD);
    ChangeWindowMessageFilter(WM_SYSCOMMAND, MSGFLT_ADD);
    ChangeWindowMessageFilter(WM_ACTIVATE, MSGFLT_ADD);

#endregion Fix bug in Windows API Code Pack

That’s it for now,
Arik Poznanski.

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  1. DanielApril 3, 2010 ב 13:05

    Hello, I just added to the api dll for the progress bar turn back to normal, just to not have to setting manually;

    it was:
    public void SetProgressValue(int currentValue, int maximumValue)
    TaskbarList.SetProgressValue(OwnerHandle, Convert.ToUInt32(currentValue), Convert.ToUInt32(maximumValue));

    and now:
    public void SetProgressValue(int currentValue, int maximumValue)
    if (currentValue >= maximumValue){ TaskbarManager.Instance.SetProgressState(TaskbarProgressBarState.NoProgress, OwnerHandle);
    TaskbarList.SetProgressValue(OwnerHandle, Convert.ToUInt32(currentValue), Convert.ToUInt32(maximumValue));

  2. Windows 8June 25, 2011 ב 07:52

    Hey thanks for sharing this informative stuff about windows 7. Its quite helpful and useful.