WPF: maximiser la fenêtre avec le problème WindowState (l'application cachera windows taskbar)

Pour continuer avec ma remarque précédente. J'utilise le code suivant dans mes applications (source: Maximizing WPF windows

using WinInterop = System.Windows.Interop;
using System.Runtime.InteropServices;

    public MainWindow()
    {
        InitializeComponent();
        winMain.SourceInitialized += new EventHandler(win_SourceInitialized);
    }


    #region Avoid hiding task bar upon maximalisation

    private static System.IntPtr WindowProc(
          System.IntPtr hwnd,
          int msg,
          System.IntPtr wParam,
          System.IntPtr lParam,
          ref bool handled)
    {
        switch (msg)
        {
            case 0x0024:
                WmGetMinMaxInfo(hwnd, lParam);
                handled = true;
                break;
        }

        return (System.IntPtr)0;
    }

    void win_SourceInitialized(object sender, EventArgs e)
    {
        System.IntPtr handle = (new WinInterop.WindowInteropHelper(this)).Handle;
        WinInterop.HwndSource.FromHwnd(handle).AddHook(new WinInterop.HwndSourceHook(WindowProc));
    }

    private static void WmGetMinMaxInfo(System.IntPtr hwnd, System.IntPtr lParam)
    {

        MINMAXINFO mmi = (MINMAXINFO)Marshal.PtrToStructure(lParam, typeof(MINMAXINFO));

        // Adjust the maximized size and position to fit the work area of the correct monitor
        int MONITOR_DEFAULTTONEAREST = 0x00000002;
        System.IntPtr monitor = MonitorFromWindow(hwnd, MONITOR_DEFAULTTONEAREST);

        if (monitor != System.IntPtr.Zero)
        {

            MONITORINFO monitorInfo = new MONITORINFO();
            GetMonitorInfo(monitor, monitorInfo);
            RECT rcWorkArea = monitorInfo.rcWork;
            RECT rcMonitorArea = monitorInfo.rcMonitor;
            mmi.ptMaxPosition.x = Math.Abs(rcWorkArea.left - rcMonitorArea.left);
            mmi.ptMaxPosition.y = Math.Abs(rcWorkArea.top - rcMonitorArea.top);
            mmi.ptMaxSize.x = Math.Abs(rcWorkArea.right - rcWorkArea.left);
            mmi.ptMaxSize.y = Math.Abs(rcWorkArea.bottom - rcWorkArea.top);
        }

        Marshal.StructureToPtr(mmi, lParam, true);
    }

    [StructLayout(LayoutKind.Sequential)]
    public struct POINT
    {
        /// <summary>
        /// x coordinate of point.
        /// </summary>
        public int x;
        /// <summary>
        /// y coordinate of point.
        /// </summary>
        public int y;

        /// <summary>
        /// Construct a point of coordinates (x,y).
        /// </summary>
        public POINT(int x, int y)
        {
            this.x = x;
            this.y = y;
        }
    }

    [StructLayout(LayoutKind.Sequential)]
    public struct MINMAXINFO
    {
        public POINT ptReserved;
        public POINT ptMaxSize;
        public POINT ptMaxPosition;
        public POINT ptMinTrackSize;
        public POINT ptMaxTrackSize;
    };

    void win_Loaded(object sender, RoutedEventArgs e)
    {
        winMain.WindowState = WindowState.Maximized;
    }

    [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto)]
    public class MONITORINFO
    {
        /// <summary>
        /// </summary>            
        public int cbSize = Marshal.SizeOf(typeof(MONITORINFO));

        /// <summary>
        /// </summary>            
        public RECT rcMonitor = new RECT();

        /// <summary>
        /// </summary>            
        public RECT rcWork = new RECT();

        /// <summary>
        /// </summary>            
        public int dwFlags = 0;
    }

    [StructLayout(LayoutKind.Sequential, Pack = 0)]
    public struct RECT
    {
        /// <summary> Win32 </summary>
        public int left;
        /// <summary> Win32 </summary>
        public int top;
        /// <summary> Win32 </summary>
        public int right;
        /// <summary> Win32 </summary>
        public int bottom;

        /// <summary> Win32 </summary>
        public static readonly RECT Empty = new RECT();

        /// <summary> Win32 </summary>
        public int Width
        {
            get { return Math.Abs(right - left); }  // Abs needed for BIDI OS
        }
        /// <summary> Win32 </summary>
        public int Height
        {
            get { return bottom - top; }
        }

        /// <summary> Win32 </summary>
        public RECT(int left, int top, int right, int bottom)
        {
            this.left = left;
            this.top = top;
            this.right = right;
            this.bottom = bottom;
        }


        /// <summary> Win32 </summary>
        public RECT(RECT rcSrc)
        {
            this.left = rcSrc.left;
            this.top = rcSrc.top;
            this.right = rcSrc.right;
            this.bottom = rcSrc.bottom;
        }

        /// <summary> Win32 </summary>
        public bool IsEmpty
        {
            get
            {
                // BUGBUG : On Bidi OS (hebrew arabic) left > right
                return left >= right || top >= bottom;
            }
        }
        /// <summary> Return a user friendly representation of this struct </summary>
        public override string ToString()
        {
            if (this == RECT.Empty) { return "RECT {Empty}"; }
            return "RECT { left : " + left + " / top : " + top + " / right : " + right + " / bottom : " + bottom + " }";
        }

        /// <summary> Determine if 2 RECT are equal (deep compare) </summary>
        public override bool Equals(object obj)
        {
            if (!(obj is Rect)) { return false; }
            return (this == (RECT)obj);
        }

        /// <summary>Return the HashCode for this struct (not garanteed to be unique)</summary>
        public override int GetHashCode()
        {
            return left.GetHashCode() + top.GetHashCode() + right.GetHashCode() + bottom.GetHashCode();
        }


        /// <summary> Determine if 2 RECT are equal (deep compare)</summary>
        public static bool operator ==(RECT rect1, RECT rect2)
        {
            return (rect1.left == rect2.left && rect1.top == rect2.top && rect1.right == rect2.right && rect1.bottom == rect2.bottom);
        }

        /// <summary> Determine if 2 RECT are different(deep compare)</summary>
        public static bool operator !=(RECT rect1, RECT rect2)
        {
            return !(rect1 == rect2);
        }


    }

    [DllImport("user32")]
    internal static extern bool GetMonitorInfo(IntPtr hMonitor, MONITORINFO lpmi);

    [DllImport("user32.dll")]
    static extern bool GetCursorPos(ref Point lpPoint);

    [DllImport("User32")]
    internal static extern IntPtr MonitorFromWindow(IntPtr handle, int flags);

    #endregion

j'ai simplifié Geoffrey de réponse un peu pour ne pas avoir à invoquer quoi que ce soit.

    public MainWindow()
    {
        InitializeComponent();
        winMain.SourceInitialized += new EventHandler(win_SourceInitialized);
    }

    void win_SourceInitialized( object sender, System.EventArgs e )
    {
        var handle = (new WindowInteropHelper( _attachedElement )).Handle;
        var handleSource = HwndSource.FromHwnd( handle );
        if ( handleSource == null )
            return;
        handleSource.AddHook( WindowProc );
    }

    private static IntPtr WindowProc( IntPtr hwnd, int msg, IntPtr wParam, IntPtr lParam, ref bool handled )
    {
        switch ( msg )
        {
            case 0x0024:/* WM_GETMINMAXINFO */
                WmGetMinMaxInfo( hwnd, lParam );
                handled = true;
                break;
        }

        return (IntPtr)0;
    }

    private static void WmGetMinMaxInfo( IntPtr hwnd, IntPtr lParam )
    {

        var mmi = (MINMAXINFO)Marshal.PtrToStructure( lParam, typeof( MINMAXINFO ) );

        // Adjust the maximized size and position to fit the work area of the correct monitor
        var currentScreen = System.Windows.Forms.Screen.FromHandle( hwnd );
        var workArea = currentScreen.WorkingArea;
        var monitorArea = currentScreen.Bounds;
        mmi.ptMaxPosition.x = Math.Abs( workArea.Left - monitorArea.Left );
        mmi.ptMaxPosition.y = Math.Abs( workArea.Top - monitorArea.Top );
        mmi.ptMaxSize.x = Math.Abs( workArea.Right - workArea.Left );
        mmi.ptMaxSize.y = Math.Abs( workArea.Bottom - workArea.Top );

        Marshal.StructureToPtr( mmi, lParam, true );
    }
}


[StructLayout( LayoutKind.Sequential )]
public struct MINMAXINFO
{
    public POINT ptReserved;
    public POINT ptMaxSize;
    public POINT ptMaxPosition;
    public POINT ptMinTrackSize;
    public POINT ptMaxTrackSize;
};

[StructLayout( LayoutKind.Sequential )]
public struct POINT
{
    /// <summary>
    /// x coordinate of point.
    /// </summary>
    public int x;
    /// <summary>
    /// y coordinate of point.
    /// </summary>
    public int y;

    /// <summary>
    /// Construct a point of coordinates (x,y).
    /// </summary>
    public POINT( int x, int y )
    {
        this.x = x;
        this.y = y;
    }
}