How do you do AppBar docking (to screen edge, like WinAmp) in WPF?

Question

Is there any complete guidance on doing AppBar docking (such as locking to the screen edge) in WPF? I understand there are InterOp calls that need to be made, but I'm looking for either a proof of concept based on a simple WPF form, or a componentized version that can be consumed.

Related resources:

Philip Rieck · Accepted Answer · 2014-12-15T15:19:27.703

Please Note: This question gathered a good amount of feedback, and some people below have made great points or fixes. Therefore, while I'll keep the code here (and possibly update it), I've also created a WpfAppBar project on github. Feel free to send pull requests.

That same project also builds to a WpfAppBar nuget package

I took the code from the first link provided in the question ( http://www.codeproject.com/KB/dotnet/AppBar.aspx ) and modified it to do two things:

Work with WPF
Be "standalone" - if you put this single file in your project, you can call AppBarFunctions.SetAppBar(...) without any further modification to the window.

This approach doesn't create a base class.

To use, just call this code from anywhere within a normal wpf window (say a button click or the initialize). Note that you can not call this until AFTER the window is initialized, if the HWND hasn't been created yet (like in the constructor), an error will occur.

Make the window an appbar:

AppBarFunctions.SetAppBar( this, ABEdge.Right );

Restore the window to a normal window:

AppBarFunctions.SetAppBar( this, ABEdge.None );

Here's the full code to the file - note you'll want to change the namespace on line 7 to something apropriate.

using System;
using System.Collections.Generic;
using System.Runtime.InteropServices;
using System.Windows;
using System.Windows.Interop;
using System.Windows.Threading;

namespace AppBarApplication
{    
    public enum ABEdge : int
    {
        Left = 0,
        Top,
        Right,
        Bottom,
        None
    }

    internal static class AppBarFunctions
    {
        [StructLayout(LayoutKind.Sequential)]
        private struct RECT
        {
            public int left;
            public int top;
            public int right;
            public int bottom;
        }

        [StructLayout(LayoutKind.Sequential)]
        private struct APPBARDATA
        {
            public int cbSize;
            public IntPtr hWnd;
            public int uCallbackMessage;
            public int uEdge;
            public RECT rc;
            public IntPtr lParam;
        }

        private enum ABMsg : int
        {
            ABM_NEW = 0,
            ABM_REMOVE,
            ABM_QUERYPOS,
            ABM_SETPOS,
            ABM_GETSTATE,
            ABM_GETTASKBARPOS,
            ABM_ACTIVATE,
            ABM_GETAUTOHIDEBAR,
            ABM_SETAUTOHIDEBAR,
            ABM_WINDOWPOSCHANGED,
            ABM_SETSTATE
        }
        private enum ABNotify : int
        {
            ABN_STATECHANGE = 0,
            ABN_POSCHANGED,
            ABN_FULLSCREENAPP,
            ABN_WINDOWARRANGE
        }

        [DllImport("SHELL32", CallingConvention = CallingConvention.StdCall)]
        private static extern uint SHAppBarMessage(int dwMessage, ref APPBARDATA pData);

        [DllImport("User32.dll", CharSet = CharSet.Auto)]
        private static extern int RegisterWindowMessage(string msg);

        private class RegisterInfo
        {
            public int CallbackId { get; set; }
            public bool IsRegistered { get; set; }
            public Window Window { get; set; }
            public ABEdge Edge { get; set; }
            public WindowStyle OriginalStyle { get; set; }            
            public Point OriginalPosition { get; set; }
            public Size OriginalSize { get; set; }
            public ResizeMode OriginalResizeMode { get; set; }


            public IntPtr WndProc(IntPtr hwnd, int msg, IntPtr wParam, 
                                    IntPtr lParam, ref bool handled)
            {
                if (msg == CallbackId)
                {
                    if (wParam.ToInt32() == (int)ABNotify.ABN_POSCHANGED)
                    {
                        ABSetPos(Edge, Window);
                        handled = true;
                    }
                }
                return IntPtr.Zero;
            }

        }
        private static Dictionary<Window, RegisterInfo> s_RegisteredWindowInfo 
            = new Dictionary<Window, RegisterInfo>();
        private static RegisterInfo GetRegisterInfo(Window appbarWindow)
        {
            RegisterInfo reg;
            if( s_RegisteredWindowInfo.ContainsKey(appbarWindow))
            {
                reg = s_RegisteredWindowInfo[appbarWindow];
            }
            else
            {
                reg = new RegisterInfo()
                    {
                        CallbackId = 0,
                        Window = appbarWindow,
                        IsRegistered = false,
                        Edge = ABEdge.Top,
                        OriginalStyle = appbarWindow.WindowStyle,                        
                        OriginalPosition =new Point( appbarWindow.Left, appbarWindow.Top),
                        OriginalSize = 
                            new Size( appbarWindow.ActualWidth, appbarWindow.ActualHeight),
                        OriginalResizeMode = appbarWindow.ResizeMode,
                    };
                s_RegisteredWindowInfo.Add(appbarWindow, reg);
            }
            return reg;
        }

        private static void RestoreWindow(Window appbarWindow)
        {
            RegisterInfo info = GetRegisterInfo(appbarWindow);

            appbarWindow.WindowStyle = info.OriginalStyle;            
            appbarWindow.ResizeMode = info.OriginalResizeMode;
            appbarWindow.Topmost = false;

            Rect rect = new Rect(info.OriginalPosition.X, info.OriginalPosition.Y, 
                info.OriginalSize.Width, info.OriginalSize.Height);
            appbarWindow.Dispatcher.BeginInvoke(DispatcherPriority.ApplicationIdle,
                    new ResizeDelegate(DoResize), appbarWindow, rect);

        }

        public static void SetAppBar(Window appbarWindow, ABEdge edge)
        {
            RegisterInfo info = GetRegisterInfo(appbarWindow);
            info.Edge = edge;

            APPBARDATA abd = new APPBARDATA();
            abd.cbSize = Marshal.SizeOf(abd);
            abd.hWnd = new WindowInteropHelper(appbarWindow).Handle;

            if( edge == ABEdge.None)
            {
                if( info.IsRegistered)
                {
                    SHAppBarMessage((int)ABMsg.ABM_REMOVE, ref abd);
                    info.IsRegistered = false;
                }
                RestoreWindow(appbarWindow);
                return;
            }

            if (!info.IsRegistered)
            {
                info.IsRegistered = true; 
                info.CallbackId = RegisterWindowMessage("AppBarMessage");
                abd.uCallbackMessage = info.CallbackId;

                uint ret = SHAppBarMessage((int)ABMsg.ABM_NEW, ref abd);

                HwndSource source = HwndSource.FromHwnd(abd.hWnd);
                source.AddHook(new HwndSourceHook(info.WndProc));
            }

            appbarWindow.WindowStyle = WindowStyle.None;            
            appbarWindow.ResizeMode = ResizeMode.NoResize;
            appbarWindow.Topmost = true;

            ABSetPos(info.Edge, appbarWindow);                
        }

        private delegate void ResizeDelegate(Window appbarWindow, Rect rect);
        private static void DoResize(Window appbarWindow, Rect rect)
        {
            appbarWindow.Width = rect.Width;
            appbarWindow.Height = rect.Height;
            appbarWindow.Top = rect.Top;
            appbarWindow.Left = rect.Left;
        }



        private static void ABSetPos(ABEdge edge, Window appbarWindow)
        {
            APPBARDATA barData = new APPBARDATA();
            barData.cbSize = Marshal.SizeOf(barData);
            barData.hWnd = new WindowInteropHelper(appbarWindow).Handle;
            barData.uEdge = (int)edge;

            if (barData.uEdge == (int)ABEdge.Left || barData.uEdge == (int)ABEdge.Right)
            {
                barData.rc.top = 0;
                barData.rc.bottom = (int)SystemParameters.PrimaryScreenHeight;
                if (barData.uEdge == (int)ABEdge.Left)
                {
                    barData.rc.left = 0;
                    barData.rc.right = (int)Math.Round(appbarWindow.ActualWidth);
                }
                else
                {
                    barData.rc.right = (int)SystemParameters.PrimaryScreenWidth;
                    barData.rc.left = barData.rc.right - (int)Math.Round(appbarWindow.ActualWidth);
                }
            }
            else
            {
                barData.rc.left = 0;
                barData.rc.right = (int)SystemParameters.PrimaryScreenWidth;
                if (barData.uEdge == (int)ABEdge.Top)
                {
                    barData.rc.top = 0;
                    barData.rc.bottom = (int)Math.Round(appbarWindow.ActualHeight);
                }
                else
                {
                    barData.rc.bottom = (int)SystemParameters.PrimaryScreenHeight;
                    barData.rc.top = barData.rc.bottom - (int)Math.Round(appbarWindow.ActualHeight);
                }
            }

            SHAppBarMessage((int)ABMsg.ABM_QUERYPOS, ref barData);
            SHAppBarMessage((int)ABMsg.ABM_SETPOS, ref barData);

            Rect rect = new Rect((double)barData.rc.left, (double)barData.rc.top, 
                (double)(barData.rc.right - barData.rc.left), (double)(barData.rc.bottom - barData.rc.top));
            //This is done async, because WPF will send a resize after a new appbar is added.  
            //if we size right away, WPFs resize comes last and overrides us.
            appbarWindow.Dispatcher.BeginInvoke(DispatcherPriority.ApplicationIdle, 
                new ResizeDelegate(DoResize), appbarWindow, rect);
        }
    }
}

This looks pretty complete, thanks for taking the time. I haven't tried it out yet, but it should be a good starting point. Thanks! — paulwhit, Sep 18 '08 at 09:49
Well done on figuring out why the damn thing moves the window if you use any other window style than None. Kudos. — Jonathan C Dickinson, Oct 28 '08 at 13:41
The is a ever-so slight problem with the logic. If you try change the docking (from top to left for example) your code using the current width and height of the window: it fills the entire screen. I fixed it by indexing the registered windows with an IntPtr and sending the RegisterInfo to ABSetPos() — Jonathan C Dickinson, Oct 28 '08 at 15:39
Don't forget to undock in the forms Closing event: AppBarFunctions.SetAppBar(this, ABEdge.None); — chilltemp, Oct 31 '08 at 16:32
If you package this code in a class library like I did, you'll have to change the access modifier from `internal` to `public`. Excellent code, saved me a lot of time. — Factor Mystic, Nov 10 '08 at 23:41
This is a fantastic implementation, good work, and Thank you :-). There are a few bugs in situations where other docked applications on the desktop change size or stop docking. I tried a situation where the windows task bar is docked to the top, and tried to dock my application to the top as well. The task bar is 40 px high and my app is 80 px, the result was that my app's height was reduced to 40 and it appeared in the wrong place. I also tried to move the task bar while my application was docked and that caused the app to move further down instead of up... — Kobi Hari, Feb 26 '14 at 15:16
@KobiHari I see some other changes on this page as well - I made this into a nuget package with the source on github, and I'll try to revisit it myself (if I get a pull request, I'll put it in nearly immediately). If you dont' want to add a pull request, feel free to add an issue with steps or a test (woohoo, test!) and I'll try to get to that as well. — Philip Rieck, Feb 26 '14 at 23:44
@Philip Rieck for WPF this solution works OK if windows DPI is at normal level (96 dpi) if you set up something different ex. 150% then AppBar stats to overflow other elements — torpederos, Sep 05 '14 at 11:20
@torpederos I wish I could +1000 your comment because I ran into this issue on my Work Computer!!! My home computer it worked fine, but then after reading your comment I went and looked at the DPI on my work computer and it was at 125% causing some really weird alignment issues. — Dustin Jensen, Feb 18 '15 at 00:29
Great solution. I used the git hub code and it worked for me. I docked the bar to the bottom edge above task bar. But some times when the taskbar thumbnails don't appear OR when I use remote connection then the opened window list from a task bar icon gets hidden behind the App bar. How can I avoid this? — KhannaB7, Sep 21 '17 at 11:49
Is there a way to choose which screen to apply? For example, I have 2 monitors, how can I set the the appbar to be in the second monitor? — JobaDiniz, Oct 20 '17 at 20:09

Mitch · Answer 2 · 2023-05-16T22:08:27.133

There is an excellent MSDN article from 1996 which is entertainingly up to date: Extend the Windows 95 Shell with Application Desktop Toolbars. Following its guidance produces an WPF based appbar which handles a number of scenarios that the other answers on this page do not:

Allow dock to any side of the screen
Allow dock to a particular monitor
Allow resizing of the appbar (if desired)
Handle screen layout changes and monitor disconnections
Handle Win + Shift + Left and attempts to minimize or move the window
Handle co-operation with other appbars (OneNote et al.)
Handle per-monitor DPI scaling

I have both a demo app and the implementation of AppBarWindow on GitHub and as a Nuget module.

Example use:

<apb:AppBarWindow x:Class="WpfAppBarDemo.MainWindow" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:apb="clr-namespace:WpfAppBar;assembly=WpfAppBar"
    DataContext="{Binding RelativeSource={RelativeSource Self}}" Title="MainWindow" 
    DockedWidthOrHeight="200" MinHeight="100" MinWidth="100">
    <Grid>
        <Button x:Name="btClose" Content="Close" HorizontalAlignment="Left" VerticalAlignment="Top" Width="75" Height="23" Margin="10,10,0,0" Click="btClose_Click"/>
        <ComboBox x:Name="cbMonitor" SelectedItem="{Binding Path=Monitor, Mode=TwoWay}" HorizontalAlignment="Left" VerticalAlignment="Top" Width="120" Margin="10,38,0,0"/>
        <ComboBox x:Name="cbEdge" SelectedItem="{Binding Path=DockMode, Mode=TwoWay}" HorizontalAlignment="Left" Margin="10,65,0,0" VerticalAlignment="Top" Width="120"/>

        <Thumb Width="5" HorizontalAlignment="Right" Background="Gray" x:Name="rzThumb" Cursor="SizeWE" DragCompleted="rzThumb_DragCompleted" />
    </Grid>
</apb:AppBarWindow>

Codebehind:

public partial class MainWindow
{
    public MainWindow()
    {
        InitializeComponent();

        this.cbEdge.ItemsSource = new[]
        {
            AppBarDockMode.Left,
            AppBarDockMode.Right,
            AppBarDockMode.Top,
            AppBarDockMode.Bottom
        };
        this.cbMonitor.ItemsSource = MonitorInfo.GetAllMonitors();
    }

    private void btClose_Click(object sender, RoutedEventArgs e)
    {
        Close();
    }

    private void rzThumb_DragCompleted(object sender, DragCompletedEventArgs e)
    {
        this.DockedWidthOrHeight += (int)(e.HorizontalChange / VisualTreeHelper.GetDpi(this).PixelsPerDip);
    }
}

Changing docked position:

Resizing with thumb:

Cooperation with other appbars:

Clone from GitHub if you want to use it. The library itself is only three files, and can easily be dropped in a project.

I ran the sample project on a dual monitor setup and it was rather buggy. I could only resize when docked left or right, and it crashed within 30 seconds due to a negative height value. I don't have time to debug it or I'd give you more info. — Dan Bechard, Jun 02 '17 at 18:55
@Dan, I am sorry to hear you had such issues. This code is widely deployed and I don't believe those are problems with `AppBarWindow` - but with the sample project. Please see [commit 84a3720](https://github.com/mgaffigan/WpfAppBar/commit/84a3720fd3e7ce4023a9a98e143763f15f3fff0a) for improvements to the demo app which account for the problems you saw. — Mitch, Jun 04 '17 at 19:22
This is a solid solution, it's definitely the smoothest. I am trying to work through one bug with the sample app where it doesn't position correctly going from bottom to right (if there are additional monitors that extend the desktop in that direction). What's perplexing about it is the calls to SHAppBarMessage send the same stuff when it works and when it doesn't (which makes me wonder if it's under the hood). — b.pell, Oct 06 '21 at 23:22

score 4 · Answer 3 · answered Sep 19 '13 at 13:53

I modified code from Philip Rieck (btw. Thanks a lot) to work in multiple display settings. Here's my solution.

using System;
using System.Collections.Generic;
using System.Runtime.InteropServices;
using System.Windows;
using System.Windows.Interop;
using System.Windows.Threading;

namespace AppBarApplication
{
    public enum ABEdge : int
    {
        Left = 0,
        Top,
        Right,
        Bottom,
        None
    }

    internal static class AppBarFunctions
    {
        [StructLayout(LayoutKind.Sequential)]
        private struct RECT
        {
            public int left;
            public int top;
            public int right;
            public int bottom;
        }

        [StructLayout(LayoutKind.Sequential)]
        private struct APPBARDATA
        {
            public int cbSize;
            public IntPtr hWnd;
            public int uCallbackMessage;
            public int uEdge;
            public RECT rc;
            public IntPtr lParam;
        }

        [StructLayout(LayoutKind.Sequential)]
        private struct MONITORINFO
        {
          public int cbSize;
          public RECT  rcMonitor;
          public RECT  rcWork;
          public int dwFlags;
        }

        private enum ABMsg : int
        {
            ABM_NEW = 0,
            ABM_REMOVE,
            ABM_QUERYPOS,
            ABM_SETPOS,
            ABM_GETSTATE,
            ABM_GETTASKBARPOS,
            ABM_ACTIVATE,
            ABM_GETAUTOHIDEBAR,
            ABM_SETAUTOHIDEBAR,
            ABM_WINDOWPOSCHANGED,
            ABM_SETSTATE
        }
        private enum ABNotify : int
        {
            ABN_STATECHANGE = 0,
            ABN_POSCHANGED,
            ABN_FULLSCREENAPP,
            ABN_WINDOWARRANGE
        }

        [DllImport("SHELL32", CallingConvention = CallingConvention.StdCall)]
        private static extern uint SHAppBarMessage(int dwMessage, ref APPBARDATA pData);

        [DllImport("User32.dll", CharSet = CharSet.Auto)]
        private static extern int RegisterWindowMessage(string msg);

        [DllImport("User32.dll", CharSet = CharSet.Auto)]
        private static extern IntPtr MonitorFromWindow(IntPtr hwnd, uint dwFlags);

        [DllImport("User32.dll", CharSet = CharSet.Auto)]
        private static extern bool GetMonitorInfo(IntPtr hMonitor, ref MONITORINFO mi);


        private const int MONITOR_DEFAULTTONEAREST = 0x2;
        private const int MONITORINFOF_PRIMARY = 0x1;

        private class RegisterInfo
        {
            public int CallbackId { get; set; }
            public bool IsRegistered { get; set; }
            public Window Window { get; set; }
            public ABEdge Edge { get; set; }
            public WindowStyle OriginalStyle { get; set; }
            public Point OriginalPosition { get; set; }
            public Size OriginalSize { get; set; }
            public ResizeMode OriginalResizeMode { get; set; }


            public IntPtr WndProc(IntPtr hwnd, int msg, IntPtr wParam,
                                    IntPtr lParam, ref bool handled)
            {
                if (msg == CallbackId)
                {
                    if (wParam.ToInt32() == (int)ABNotify.ABN_POSCHANGED)
                    {
                        ABSetPos(Edge, Window);
                        handled = true;
                    }
                }
                return IntPtr.Zero;
            }

        }
        private static Dictionary<Window, RegisterInfo> s_RegisteredWindowInfo
            = new Dictionary<Window, RegisterInfo>();
        private static RegisterInfo GetRegisterInfo(Window appbarWindow)
        {
            RegisterInfo reg;
            if (s_RegisteredWindowInfo.ContainsKey(appbarWindow))
            {
                reg = s_RegisteredWindowInfo[appbarWindow];
            }
            else
            {
                reg = new RegisterInfo()
                {
                    CallbackId = 0,
                    Window = appbarWindow,
                    IsRegistered = false,
                    Edge = ABEdge.Top,
                    OriginalStyle = appbarWindow.WindowStyle,
                    OriginalPosition = new Point(appbarWindow.Left, appbarWindow.Top),
                    OriginalSize =
                        new Size(appbarWindow.ActualWidth, appbarWindow.ActualHeight),
                    OriginalResizeMode = appbarWindow.ResizeMode,
                };
                s_RegisteredWindowInfo.Add(appbarWindow, reg);
            }
            return reg;
        }

        private static void RestoreWindow(Window appbarWindow)
        {
            RegisterInfo info = GetRegisterInfo(appbarWindow);

            appbarWindow.WindowStyle = info.OriginalStyle;
            appbarWindow.ResizeMode = info.OriginalResizeMode;
            appbarWindow.Topmost = false;

            Rect rect = new Rect(info.OriginalPosition.X, info.OriginalPosition.Y,
                info.OriginalSize.Width, info.OriginalSize.Height);
            appbarWindow.Dispatcher.BeginInvoke(DispatcherPriority.ApplicationIdle,
                    new ResizeDelegate(DoResize), appbarWindow, rect);

        }

        public static void SetAppBar(Window appbarWindow, ABEdge edge)
        {
            RegisterInfo info = GetRegisterInfo(appbarWindow);

            info.Edge = edge;

            APPBARDATA abd = new APPBARDATA();
            abd.cbSize = Marshal.SizeOf(abd);
            abd.hWnd = new WindowInteropHelper(appbarWindow).Handle;

            if (edge == ABEdge.None)
            {
                if (info.IsRegistered)
                {
                    SHAppBarMessage((int)ABMsg.ABM_REMOVE, ref abd);
                    info.IsRegistered = false;
                }
                RestoreWindow(appbarWindow);
                return;
            }

            if (!info.IsRegistered)
            {
                info.IsRegistered = true;
                info.CallbackId = RegisterWindowMessage("AppBarMessage");
                abd.uCallbackMessage = info.CallbackId;

                uint ret = SHAppBarMessage((int)ABMsg.ABM_NEW, ref abd);

                HwndSource source = HwndSource.FromHwnd(abd.hWnd);
                source.AddHook(new HwndSourceHook(info.WndProc));
            }

            appbarWindow.WindowStyle = WindowStyle.None;
            appbarWindow.ResizeMode = ResizeMode.NoResize;
            appbarWindow.Topmost = true;

            ABSetPos(info.Edge, appbarWindow);
        }

        private delegate void ResizeDelegate(Window appbarWindow, Rect rect);
        private static void DoResize(Window appbarWindow, Rect rect)
        {
            appbarWindow.Width = rect.Width;
            appbarWindow.Height = rect.Height;
            appbarWindow.Top = rect.Top;
            appbarWindow.Left = rect.Left;
        }

        private static void GetActualScreenData(ABEdge edge, Window appbarWindow, ref int leftOffset, ref int topOffset, ref int actualScreenWidth, ref int actualScreenHeight)
        {
            IntPtr handle = new WindowInteropHelper(appbarWindow).Handle;
            IntPtr monitorHandle = MonitorFromWindow(handle, MONITOR_DEFAULTTONEAREST);

            MONITORINFO mi = new MONITORINFO();
            mi.cbSize = Marshal.SizeOf(mi);

            if (GetMonitorInfo(monitorHandle, ref mi))
            {
                if (mi.dwFlags == MONITORINFOF_PRIMARY)
                {
                    return;
                }
                leftOffset = mi.rcWork.left;
                topOffset = mi.rcWork.top;
                actualScreenWidth = mi.rcWork.right - leftOffset;
                actualScreenHeight = mi.rcWork.bottom - mi.rcWork.top;
            }
        }

        private static void ABSetPos(ABEdge edge, Window appbarWindow)
        {
            APPBARDATA barData = new APPBARDATA();
            barData.cbSize = Marshal.SizeOf(barData);
            barData.hWnd = new WindowInteropHelper(appbarWindow).Handle;
            barData.uEdge = (int)edge;

            int leftOffset = 0;
            int topOffset = 0;
            int actualScreenWidth = (int)SystemParameters.PrimaryScreenWidth;
            int actualScreenHeight = (int)SystemParameters.PrimaryScreenHeight;

            GetActualScreenData(edge, appbarWindow, ref leftOffset, ref topOffset, ref actualScreenWidth, ref actualScreenHeight);

            if (barData.uEdge == (int)ABEdge.Left || barData.uEdge == (int)ABEdge.Right)
            {
                barData.rc.top = topOffset;
                barData.rc.bottom = actualScreenHeight;
                if (barData.uEdge == (int)ABEdge.Left)
                {
                    barData.rc.left = leftOffset;
                    barData.rc.right = (int)Math.Round(appbarWindow.ActualWidth) + leftOffset;
                }
                else
                {
                    barData.rc.right = actualScreenWidth + leftOffset;
                    barData.rc.left = barData.rc.right - (int)Math.Round(appbarWindow.ActualWidth);
                }
            }
            else
            {
                barData.rc.left = leftOffset;
                barData.rc.right = actualScreenWidth + leftOffset;
                if (barData.uEdge == (int)ABEdge.Top)
                {
                    barData.rc.top = topOffset;
                    barData.rc.bottom = (int)Math.Round(appbarWindow.ActualHeight) + topOffset;
                }
                else
                {
                    barData.rc.bottom = actualScreenHeight + topOffset;
                    barData.rc.top = barData.rc.bottom - (int)Math.Round(appbarWindow.ActualHeight);
                }
            }

            SHAppBarMessage((int)ABMsg.ABM_QUERYPOS, ref barData);
            SHAppBarMessage((int)ABMsg.ABM_SETPOS, ref barData);

            Rect rect = new Rect((double)barData.rc.left, (double)barData.rc.top,
                (double)(barData.rc.right - barData.rc.left), (double)(barData.rc.bottom - barData.rc.top));
            //This is done async, because WPF will send a resize after a new appbar is added.  
            //if we size right away, WPFs resize comes last and overrides us.
            appbarWindow.Dispatcher.BeginInvoke(DispatcherPriority.ApplicationIdle,
                new ResizeDelegate(DoResize), appbarWindow, rect);
        }
    }
}

score 4 · Answer 4 · answered Apr 10 '11 at 06:39

Sorry for my English... Here is the Philip Rieck's solution with some corrects. It correctly works with Taskbar position and size changes.

using System;
using System.Collections.Generic;
using System.Runtime.InteropServices;
using System.Windows;
using System.Windows.Interop;
using System.Windows.Threading;

namespace wpf_appbar
{
    public enum ABEdge : int
    {
        Left,
        Top,
        Right,
        Bottom,
        None
    }

    internal static class AppBarFunctions
    {
        [StructLayout(LayoutKind.Sequential)]
        private struct RECT
        {
            public int Left;
            public int Top;
            public int Right;
            public int Bottom;
            public RECT(Rect r)
            {
                Left = (int)r.Left;
                Right = (int)r.Right;
                Top = (int)r.Top;
                Bottom = (int)r.Bottom;
            }
            public static bool operator ==(RECT r1, RECT r2)
            {
                return r1.Bottom == r2.Bottom && r1.Left == r2.Left && r1.Right == r2.Right && r1.Top == r2.Top;
            }
            public static bool operator !=(RECT r1, RECT r2)
            {
                return !(r1 == r2);
            }
            public override bool Equals(object obj)
            {
                return base.Equals(obj);
            }
            public override int GetHashCode()
            {
                return base.GetHashCode();
            }
        }

        [StructLayout(LayoutKind.Sequential)]
        private struct APPBARDATA
        {
            public int cbSize;
            public IntPtr hWnd;
            public int uCallbackMessage;
            public int uEdge;
            public RECT rc;
            public IntPtr lParam;
        }

        private enum ABMsg : int
        {
            ABM_NEW = 0,
            ABM_REMOVE,
            ABM_QUERYPOS,
            ABM_SETPOS,
            ABM_GETSTATE,
            ABM_GETTASKBARPOS,
            ABM_ACTIVATE,
            ABM_GETAUTOHIDEBAR,
            ABM_SETAUTOHIDEBAR,
            ABM_WINDOWPOSCHANGED,
            ABM_SETSTATE
        }
        private enum ABNotify : int
        {
            ABN_STATECHANGE = 0,
            ABN_POSCHANGED,
            ABN_FULLSCREENAPP,
            ABN_WINDOWARRANGE
        }

        private enum TaskBarPosition : int
        {
            Left,
            Top,
            Right,
            Bottom
        }

        [StructLayout(LayoutKind.Sequential)]
        class TaskBar
        {
            public TaskBarPosition Position;
            public TaskBarPosition PreviousPosition;
            public RECT Rectangle;
            public RECT PreviousRectangle;
            public int Width;
            public int PreviousWidth;
            public int Height;
            public int PreviousHeight;
            public TaskBar()
            {
                Refresh();
            }
            public void Refresh()
            {
                APPBARDATA msgData = new APPBARDATA();
                msgData.cbSize = Marshal.SizeOf(msgData);
                SHAppBarMessage((int)ABMsg.ABM_GETTASKBARPOS, ref msgData);
                PreviousPosition = Position;
                PreviousRectangle = Rectangle;
                PreviousHeight = Height;
                PreviousWidth = Width;
                Rectangle = msgData.rc;
                Width = Rectangle.Right - Rectangle.Left;
                Height = Rectangle.Bottom - Rectangle.Top;
                int h = (int)SystemParameters.PrimaryScreenHeight;
                int w = (int)SystemParameters.PrimaryScreenWidth;
                if (Rectangle.Bottom == h && Rectangle.Top != 0) Position = TaskBarPosition.Bottom;
                else if (Rectangle.Top == 0 && Rectangle.Bottom != h) Position = TaskBarPosition.Top;
                else if (Rectangle.Right == w && Rectangle.Left != 0) Position = TaskBarPosition.Right;
                else if (Rectangle.Left == 0 && Rectangle.Right != w) Position = TaskBarPosition.Left;
            }
        }

        [DllImport("SHELL32", CallingConvention = CallingConvention.StdCall)]
        private static extern uint SHAppBarMessage(int dwMessage, ref APPBARDATA pData);

        [DllImport("User32.dll", CharSet = CharSet.Auto)]
        private static extern int RegisterWindowMessage(string msg);

        private class RegisterInfo
        {
            public int CallbackId { get; set; }
            public bool IsRegistered { get; set; }
            public Window Window { get; set; }
            public ABEdge Edge { get; set; }
            public ABEdge PreviousEdge { get; set; }
            public WindowStyle OriginalStyle { get; set; }
            public Point OriginalPosition { get; set; }
            public Size OriginalSize { get; set; }
            public ResizeMode OriginalResizeMode { get; set; }


            public IntPtr WndProc(IntPtr hwnd, int msg, IntPtr wParam,
                                    IntPtr lParam, ref bool handled)
            {
                if (msg == CallbackId)
                {
                    if (wParam.ToInt32() == (int)ABNotify.ABN_POSCHANGED)
                    {
                        PreviousEdge = Edge;
                        ABSetPos(Edge, PreviousEdge, Window);
                        handled = true;
                    }
                }
                return IntPtr.Zero;
            }

        }
        private static Dictionary<Window, RegisterInfo> s_RegisteredWindowInfo
            = new Dictionary<Window, RegisterInfo>();
        private static RegisterInfo GetRegisterInfo(Window appbarWindow)
        {
            RegisterInfo reg;
            if (s_RegisteredWindowInfo.ContainsKey(appbarWindow))
            {
                reg = s_RegisteredWindowInfo[appbarWindow];
            }
            else
            {
                reg = new RegisterInfo()
                {
                    CallbackId = 0,
                    Window = appbarWindow,
                    IsRegistered = false,
                    Edge = ABEdge.None,
                    PreviousEdge = ABEdge.None,
                    OriginalStyle = appbarWindow.WindowStyle,
                    OriginalPosition = new Point(appbarWindow.Left, appbarWindow.Top),
                    OriginalSize =
                        new Size(appbarWindow.ActualWidth, appbarWindow.ActualHeight),
                    OriginalResizeMode = appbarWindow.ResizeMode,
                };
                s_RegisteredWindowInfo.Add(appbarWindow, reg);
            }
            return reg;
        }

        private static void RestoreWindow(Window appbarWindow)
        {
            RegisterInfo info = GetRegisterInfo(appbarWindow);

            appbarWindow.WindowStyle = info.OriginalStyle;
            appbarWindow.ResizeMode = info.OriginalResizeMode;
            appbarWindow.Topmost = false;

            Rect rect = new Rect(info.OriginalPosition.X, info.OriginalPosition.Y,
                info.OriginalSize.Width, info.OriginalSize.Height);
            appbarWindow.Dispatcher.BeginInvoke(DispatcherPriority.ApplicationIdle,
                    new ResizeDelegate(DoResize), appbarWindow, rect);

        }


        public static void SetAppBar(Window appbarWindow, ABEdge edge)
        {
            RegisterInfo info = GetRegisterInfo(appbarWindow);
            info.Edge = edge;

            APPBARDATA abd = new APPBARDATA();
            abd.cbSize = Marshal.SizeOf(abd);
            abd.hWnd = new WindowInteropHelper(appbarWindow).Handle;

            if (edge == ABEdge.None)
            {
                if (info.IsRegistered)
                {
                    SHAppBarMessage((int)ABMsg.ABM_REMOVE, ref abd);
                    info.IsRegistered = false;
                }
                RestoreWindow(appbarWindow);
                info.PreviousEdge = info.Edge;
                return;
            }

            if (!info.IsRegistered)
            {
                info.IsRegistered = true;
                info.CallbackId = RegisterWindowMessage("AppBarMessage");
                abd.uCallbackMessage = info.CallbackId;

                uint ret = SHAppBarMessage((int)ABMsg.ABM_NEW, ref abd);

                HwndSource source = HwndSource.FromHwnd(abd.hWnd);
                source.AddHook(new HwndSourceHook(info.WndProc));
            }

            appbarWindow.WindowStyle = WindowStyle.None;
            appbarWindow.ResizeMode = ResizeMode.NoResize;
            appbarWindow.Topmost = true;

            ABSetPos(info.Edge, info.PreviousEdge, appbarWindow);
        }

        private delegate void ResizeDelegate(Window appbarWindow, Rect rect);
        private static void DoResize(Window appbarWindow, Rect rect)
        {
            appbarWindow.Width = rect.Width;
            appbarWindow.Height = rect.Height;
            appbarWindow.Top = rect.Top;
            appbarWindow.Left = rect.Left;
        }

        static TaskBar tb = new TaskBar();

        private static void ABSetPos(ABEdge edge, ABEdge prevEdge, Window appbarWindow)
        {
            APPBARDATA barData = new APPBARDATA();
            barData.cbSize = Marshal.SizeOf(barData);
            barData.hWnd = new WindowInteropHelper(appbarWindow).Handle;
            barData.uEdge = (int)edge;
            RECT wa = new RECT(SystemParameters.WorkArea);
            tb.Refresh();
            switch (edge)
            {
                case ABEdge.Top:
                    barData.rc.Left = wa.Left - (prevEdge == ABEdge.Left ? (int)Math.Round(appbarWindow.ActualWidth) : 0);
                    barData.rc.Right = wa.Right + (prevEdge == ABEdge.Right ? (int)Math.Round(appbarWindow.ActualWidth) : 0);
                    barData.rc.Top = wa.Top - (prevEdge == ABEdge.Top ? (int)Math.Round(appbarWindow.ActualHeight) : 0) - ((tb.Position != TaskBarPosition.Top && tb.PreviousPosition == TaskBarPosition.Top) ? tb.Height : 0) + ((tb.Position == TaskBarPosition.Top && tb.PreviousPosition != TaskBarPosition.Top) ? tb.Height : 0);
                    barData.rc.Bottom = barData.rc.Top + (int)Math.Round(appbarWindow.ActualHeight);
                    break;
                case ABEdge.Bottom:
                    barData.rc.Left = wa.Left - (prevEdge == ABEdge.Left ? (int)Math.Round(appbarWindow.ActualWidth) : 0);
                    barData.rc.Right = wa.Right + (prevEdge == ABEdge.Right ? (int)Math.Round(appbarWindow.ActualWidth) : 0);
                    barData.rc.Bottom = wa.Bottom + (prevEdge == ABEdge.Bottom ? (int)Math.Round(appbarWindow.ActualHeight) : 0) - 1 + ((tb.Position != TaskBarPosition.Bottom && tb.PreviousPosition == TaskBarPosition.Bottom) ? tb.Height : 0) - ((tb.Position == TaskBarPosition.Bottom && tb.PreviousPosition != TaskBarPosition.Bottom) ? tb.Height : 0);
                    barData.rc.Top = barData.rc.Bottom - (int)Math.Round(appbarWindow.ActualHeight);
                    break;
            }

            SHAppBarMessage((int)ABMsg.ABM_QUERYPOS, ref barData);
            switch (barData.uEdge)
            {
                case (int)ABEdge.Bottom:
                    if (tb.Position == TaskBarPosition.Bottom && tb.PreviousPosition == tb.Position)
                    {
                        barData.rc.Top += (tb.PreviousHeight - tb.Height);
                        barData.rc.Bottom = barData.rc.Top + (int)appbarWindow.ActualHeight;
                    }
                    break;
                case (int)ABEdge.Top:
                    if (tb.Position == TaskBarPosition.Top && tb.PreviousPosition == tb.Position)
                    {
                        if (tb.PreviousHeight - tb.Height > 0) barData.rc.Top -= (tb.PreviousHeight - tb.Height);
                        barData.rc.Bottom = barData.rc.Top + (int)appbarWindow.ActualHeight;
                    }
                    break;
            }
            SHAppBarMessage((int)ABMsg.ABM_SETPOS, ref barData);

            Rect rect = new Rect((double)barData.rc.Left, (double)barData.rc.Top, (double)(barData.rc.Right - barData.rc.Left), (double)(barData.rc.Bottom - barData.rc.Top));
            appbarWindow.Dispatcher.BeginInvoke(new ResizeDelegate(DoResize), DispatcherPriority.ApplicationIdle, appbarWindow, rect);
        }
    }
}

The same code you can write for the Left and Right edges. Good job, Philip Rieck, thank you!

score 4 · Answer 5 · answered Mar 08 '09 at 20:34

4

Very happy to have found this question. Above class is really useful, but doesnt quite cover all the bases of AppBar implementation.

To fully implement all the behaviour of an AppBar (cope with fullscreen apps etc) you're going to want to read this MSDN article too.

http://msdn.microsoft.com/en-us/library/bb776821.aspx

answered Mar 08 '09 at 20:34

Shuft

1,400
2
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1

Thanks for the reference. I've gotten enough comments on this code that I just put it up on github. If you want to, feel free to fork it or send pull requests. – Philip Rieck Feb 26 '14 at 23:46
How do I hook the AppBarCallback function in? I can't figure out the proper way to call it. – xandermonkey May 10 '17 at 15:09

score 2 · Answer 6 · edited Aug 14 '14 at 21:06

2

As a commercial alternative, see the ready-to-use ShellAppBar component for WPF which supports all cases and secnarios such as taskbar docked to left,right,top,bottom edge, support for multiple monitors, drag-docking, autohide , etc etc. It may save you time and money over trying to handle all these cases yourself.

DISCLAIMER: I work for LogicNP Software, the developer of ShellAppBar.

edited Aug 14 '14 at 21:06

Forest Kunecke

2,160
15
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answered Jul 13 '09 at 04:58

logicnp

5,796
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score 1 · Answer 7 · answered Oct 22 '15 at 02:16

1

I've spent some weeks exploring this challenge and finally created a very solid NuGet package delivering this functionality in very friendly way. Simply create a new WPF app then change the main window's class from Window to DockWindow (in the XAML) and that's it!

Get the package here and see the Git repo for a demonstration app.

answered Oct 22 '15 at 02:16

Hugh

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9

While this link may answer the question, it is better to include the essential parts of the answer here and provide the link for reference. Link-only answers can become invalid if the linked page changes. – President James K. Polk Oct 23 '15 at 01:43
2

@JamesKPolk: Links to a tool or library should include a specific explanation of how the linked resource is applicable to the problem, and ideally [also be accompanied by usage notes or some sample code](http://meta.stackoverflow.com/a/251605). This appears to do all that. – Nathan Tuggy Oct 23 '15 at 03:06

score 1 · Answer 8 · answered Apr 22 '09 at 20:50

Sorry, the last code I posted didn't work when the Taskbar is resized. The following code change seems to work better:

  SHAppBarMessage((int)ABMsg.ABM_QUERYPOS, ref barData);

  if (barData.uEdge == (int)ABEdge.Top)
    barData.rc.bottom = barData.rc.top + (int)Math.Round(appbarWindow.ActualHeight);
  else if (barData.uEdge == (int)ABEdge.Bottom)
    barData.rc.top = barData.rc.bottom - (int)Math.Round(appbarWindow.ActualHeight);

  SHAppBarMessage((int)ABMsg.ABM_SETPOS, ref barData);

How do you do AppBar docking (to screen edge, like WinAmp) in WPF?

8 Answers8

Linked

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