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AppBar using C#

Mad__

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18 Apr 2004

How to make AppBar for .NET

Using the Code

First we must declare the needed structures and constants.
(I combine constants in enums).

We declare the RECT WINAPI structure as follows:

[StructLayout(LayoutKind.Sequential)]
struct RECT
{
    public int left;
    public int top;
    public int right;
    public int bottom;
}

We declare the APPBARDATA SHELLAPI structure as follows:

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

Then, we declare the AppBar related constants enums as follows:

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
}
enum ABNotify : int
{
    ABN_STATECHANGE=0,
    ABN_POSCHANGED,
    ABN_FULLSCREENAPP,
    ABN_WINDOWARRANGE
}
enum ABEdge : int
{
    ABE_LEFT=0,
    ABE_TOP,
    ABE_RIGHT,
    ABE_BOTTOM
}

Next we declare the needed WIN32 and SHELL API functions import:

[DllImport("SHELL32", CallingConvention=CallingConvention.StdCall)]
static extern uint SHAppBarMessage(int dwMessage, ref APPBARDATA pData);
[DllImport("USER32")]
static extern int GetSystemMetrics(int Index);
[DllImport("User32.dll", ExactSpelling=true, 
    CharSet=System.Runtime.InteropServices.CharSet.Auto)]
private static extern bool MoveWindow
    (IntPtr hWnd, int x, int y, int cx, int cy, bool repaint);
[DllImport("User32.dll", CharSet=CharSet.Auto)]
private static extern int RegisterWindowMessage(string msg);

The next step is creating a function to register AppBar:

private void RegisterBar()
{
    APPBARDATA abd = new APPBARDATA();
    abd.cbSize = Marshal.SizeOf(abd);
    abd.hWnd = this.Handle;
    if (!fBarRegistered)
    {
        uCallBack = RegisterWindowMessage("AppBarMessage");
        abd.uCallbackMessage = uCallBack;

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

    ABSetPos();
    }
    else
    {
    SHAppBarMessage((int)ABMsg.ABM_REMOVE, ref abd);
    fBarRegistered = false;
    }
}

The last step is to create a function to position AppBar:

private void ABSetPos()
{
    APPBARDATA abd = new APPBARDATA();
    abd.cbSize = Marshal.SizeOf(abd);
    abd.hWnd = this.Handle;
    abd.uEdge = (int)ABEdge.ABE_TOP;

    if (abd.uEdge == (int)ABEdge.ABE_LEFT || abd.uEdge == (int)ABEdge.ABE_RIGHT) 
    {
    abd.rc.top = 0;
    abd.rc.bottom = SystemInformation.PrimaryMonitorSize.Height;
    if (abd.uEdge == (int)ABEdge.ABE_LEFT) 
    {
        abd.rc.left = 0;
        abd.rc.right = Size.Width;
    }
    else 
    {
        abd.rc.right = SystemInformation.PrimaryMonitorSize.Width;
        abd.rc.left = abd.rc.right - Size.Width;
    }

    }
    else 
    {
    abd.rc.left = 0;
    abd.rc.right = SystemInformation.PrimaryMonitorSize.Width;
    if (abd.uEdge == (int)ABEdge.ABE_TOP) 
    {
        abd.rc.top = 0;
        abd.rc.bottom = Size.Height;
    }
    else 
    {
        abd.rc.bottom = SystemInformation.PrimaryMonitorSize.Height;
        abd.rc.top = abd.rc.bottom - Size.Height;
    }
    }

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

    switch (abd.uEdge) 
    { 
    case (int)ABEdge.ABE_LEFT: 
        abd.rc.right = abd.rc.left + Size.Width;
        break; 
    case (int)ABEdge.ABE_RIGHT: 
        abd.rc.left= abd.rc.right - Size.Width;
        break; 
    case (int)ABEdge.ABE_TOP: 
        abd.rc.bottom = abd.rc.top + Size.Height;
        break; 
    case (int)ABEdge.ABE_BOTTOM: 
        abd.rc.top = abd.rc.bottom - Size.Height;
        break; 
    }

    SHAppBarMessage((int)ABMsg.ABM_SETPOS, ref abd); 
    MoveWindow(abd.hWnd, abd.rc.left, abd.rc.top, 
            abd.rc.right - abd.rc.left, abd.rc.bottom - abd.rc.top, true); 
}

This is a full listing of a sample AppBar form class:

using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;
using System.Runtime.InteropServices;

namespace Sample.AppBar
{
    /// <summary>
    /// Summary description for Form1.
    /// </summary>
    public class MainForm : System.Windows.Forms.Form
    {
        /// <summary>
        /// Required designer variable.
        /// </summary>
        private System.ComponentModel.Container components = null;

        public MainForm()
        {
            //
            // Required for Windows Form Designer support
            //
            InitializeComponent();

            //
            // TODO: Add any constructor code after InitializeComponent call
            //
        }

        /// <summary>
        /// Clean up any resources being used.
        /// </summary>
        protected override void Dispose( bool disposing )
        {
            if( disposing )
            {
                if (components != null) 
                {
                    components.Dispose();
                }
            }
            base.Dispose( disposing );
        }

        #region Windows Form Designer generated code
        /// <summary>
        /// Required method for Designer support - do not modify
        /// the contents of this method with the code editor.
        /// </summary>
        private void InitializeComponent()
        {
            // 
            // MainForm
            // 
            this.AutoScaleBaseSize = new System.Drawing.Size(5, 13);
            this.ClientSize = new System.Drawing.Size(960, 50);
            this.FormBorderStyle = System.Windows.Forms.FormBorderStyle.FixedToolWindow;
            this.Name = "MainForm";
            this.Text = "AppBar";
            this.Closing += new System.ComponentModel.CancelEventHandler(this.OnClosing);
            this.Load += new System.EventHandler(this.OnLoad);
        }
        #endregion

        #region APPBAR

        [StructLayout(LayoutKind.Sequential)]
        struct RECT
        {
            public int left;
            public int top;
            public int right;
            public int bottom;
        }

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

        enum ABMsg : int
        {
            ABM_NEW=0,
            ABM_REMOVE=1,
            ABM_QUERYPOS=2,
            ABM_SETPOS=3,
            ABM_GETSTATE=4,
            ABM_GETTASKBARPOS=5,
            ABM_ACTIVATE=6,
            ABM_GETAUTOHIDEBAR=7,
            ABM_SETAUTOHIDEBAR=8,
            ABM_WINDOWPOSCHANGED=9,
            ABM_SETSTATE=10
        }

        enum ABNotify : int
        {
            ABN_STATECHANGE=0,
            ABN_POSCHANGED,
            ABN_FULLSCREENAPP,
            ABN_WINDOWARRANGE
        }

        enum ABEdge : int
        {
            ABE_LEFT=0,
            ABE_TOP,
            ABE_RIGHT,
            ABE_BOTTOM
        }

        private bool fBarRegistered = false;

        [DllImport("SHELL32", CallingConvention=CallingConvention.StdCall)]
        static extern uint SHAppBarMessage(int dwMessage, ref APPBARDATA pData);
        [DllImport("USER32")]
        static extern int GetSystemMetrics(int Index);
        [DllImport("User32.dll", ExactSpelling=true, 
            CharSet=System.Runtime.InteropServices.CharSet.Auto)]
        private static extern bool MoveWindow
            (IntPtr hWnd, int x, int y, int cx, int cy, bool repaint);
        [DllImport("User32.dll", CharSet=CharSet.Auto)]
        private static extern int RegisterWindowMessage(string msg);
        private int uCallBack;

        private void RegisterBar()
        {
            APPBARDATA abd = new APPBARDATA();
            abd.cbSize = Marshal.SizeOf(abd);
            abd.hWnd = this.Handle;
            if (!fBarRegistered)
            {
                uCallBack = RegisterWindowMessage("AppBarMessage");
                abd.uCallbackMessage = uCallBack;

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

                ABSetPos();
            }
            else
            {
                SHAppBarMessage((int)ABMsg.ABM_REMOVE, ref abd);
                fBarRegistered = false;
            }
        }

        private void ABSetPos()
        {
            APPBARDATA abd = new APPBARDATA();
            abd.cbSize = Marshal.SizeOf(abd);
            abd.hWnd = this.Handle;
            abd.uEdge = (int)ABEdge.ABE_TOP;

            if (abd.uEdge == (int)ABEdge.ABE_LEFT || abd.uEdge == (int)ABEdge.ABE_RIGHT) 
            {
                abd.rc.top = 0;
                abd.rc.bottom = SystemInformation.PrimaryMonitorSize.Height;
                if (abd.uEdge == (int)ABEdge.ABE_LEFT) 
                {
                    abd.rc.left = 0;
                    abd.rc.right = Size.Width;
                }
                else 
                {
                    abd.rc.right = SystemInformation.PrimaryMonitorSize.Width;
                    abd.rc.left = abd.rc.right - Size.Width;
                }

            }
            else 
            {
                abd.rc.left = 0;
                abd.rc.right = SystemInformation.PrimaryMonitorSize.Width;
                if (abd.uEdge == (int)ABEdge.ABE_TOP) 
                {
                    abd.rc.top = 0;
                    abd.rc.bottom = Size.Height;
                }
                else 
                {
                    abd.rc.bottom = SystemInformation.PrimaryMonitorSize.Height;
                    abd.rc.top = abd.rc.bottom - Size.Height;
                }
            }

            // Query the system for an approved size and position. 
            SHAppBarMessage((int)ABMsg.ABM_QUERYPOS, ref abd); 

            // Adjust the rectangle, depending on the edge to which the 
            // appbar is anchored. 
            switch (abd.uEdge) 
            { 
                case (int)ABEdge.ABE_LEFT: 
                    abd.rc.right = abd.rc.left + Size.Width;
                    break; 
                case (int)ABEdge.ABE_RIGHT: 
                    abd.rc.left= abd.rc.right - Size.Width;
                    break; 
                case (int)ABEdge.ABE_TOP: 
                    abd.rc.bottom = abd.rc.top + Size.Height;
                    break; 
                case (int)ABEdge.ABE_BOTTOM: 
                    abd.rc.top = abd.rc.bottom - Size.Height;
                    break; 
            }

            // Pass the final bounding rectangle to the system. 
            SHAppBarMessage((int)ABMsg.ABM_SETPOS, ref abd); 

            // Move and size the appbar so that it conforms to the 
            // bounding rectangle passed to the system. 
            MoveWindow(abd.hWnd, abd.rc.left, abd.rc.top, 
                abd.rc.right - abd.rc.left, abd.rc.bottom - abd.rc.top, true); 
        }

        protected override void WndProc(ref System.Windows.Forms.Message m)
        {
            if (m.Msg == uCallBack)
            {
                switch(m.WParam.ToInt32())
                {
                    case (int)ABNotify.ABN_POSCHANGED:
                        ABSetPos();
                        break;
                }
            }

            base.WndProc(ref m);
        }

        protected override System.Windows.Forms.CreateParams CreateParams
        {
            get
            {
                CreateParams cp = base.CreateParams;
                cp.Style &= (~0x00C00000); // WS_CAPTION
                cp.Style &= (~0x00800000); // WS_BORDER
                cp.ExStyle = 0x00000080 | 0x00000008; // WS_EX_TOOLWINDOW | WS_EX_TOPMOST
                return cp;
            }
        }

        #endregion

        /// <summary>
        /// The main entry point for the application.
        /// </summary>
        [STAThread]
        static void Main() 
        {
            Application.Run(new MainForm());
        }

        private void OnLoad(object sender, System.EventArgs e)
        {
            RegisterBar();
        }

        private void OnClosing(object sender, System.ComponentModel.CancelEventArgs e)
        {
            RegisterBar();
        }
    }
}

For more information about creating AppBars, refer to the MSDN.

P.S.

Post in comments and questions about code parts. I plan to update the article descriptions based on your questions.

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