避免窗口最大化时遮盖任务栏

WPF窗口最大化时有个很不好的现象是：如果窗口的WindowStyle被直接或间接地设置为None，那么最大化窗口后，窗口将铺满整个屏幕而将任务栏盖住。

调用FullScreenManager.RepairWpfWindowFullScreenBehavior(this)；

 

public static class FullScreenManager
    {
        public static void RepairWpfWindowFullScreenBehavior(Window wpfWindow)
        {
            if (wpfWindow == null)
            {
                return;
            }

            if (wpfWindow.WindowState == WindowState.Maximized)
            {
                wpfWindow.WindowState = WindowState.Normal;
                wpfWindow.Loaded += delegate { wpfWindow.WindowState = WindowState.Maximized; };
            }

            wpfWindow.SourceInitialized += delegate
            {
                IntPtr handle = (new WindowInteropHelper(wpfWindow)).Handle;
                HwndSource source = HwndSource.FromHwnd(handle);
                if (source != null)
                {
                    source.AddHook(WindowProc);
                }
            };
        }

        private static IntPtr WindowProc(IntPtr hwnd, int msg, IntPtr wParam, IntPtr lParam, ref bool handled)
        {
            switch (msg)
            {
                case 0x0024:
                    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
            int MONITOR_DEFAULTTONEAREST = 0x00000002;
            IntPtr monitor = MonitorFromWindow(hwnd, MONITOR_DEFAULTTONEAREST);

            if (monitor != IntPtr.Zero)
            {
                var 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);
        }


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

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

        #region Nested type: MINMAXINFO

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

        #endregion

        #region Nested type: MONITORINFO

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

            /// <summary>
            /// </summary>            
            public RECT rcMonitor;

            /// <summary>
            /// </summary>            
            public RECT rcWork;

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

        #endregion

        #region Nested type: POINT

        /// <summary>
        /// POINT aka POINTAPI
        /// </summary>
        [StructLayout(LayoutKind.Sequential)]
        internal 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;
            }
        }

        #endregion

        #region Nested type: RECT

        /// <summary> Win32 </summary>
        [StructLayout(LayoutKind.Sequential, Pack = 0)]
        internal 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;

            /// <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)
            {
                left = rcSrc.left;
                top = rcSrc.top;
                right = rcSrc.right;
                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 == 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);
            }
        }

        #endregion
    }