【WPF】无边框窗体

之前写了一个支持尺寸变换的无边框窗体的一个基窗体，代码如下：

public class LBaseWindow : Window
    {
        /// <summary>
        /// 基窗体
        /// </summary>
        public LBaseWindow()
        {
            Initialize();
        }
        /// <summary>
        /// 是否显示任务栏，如果任务栏不显示，则窗体覆盖整个屏幕
        /// </summary>
        public Visibility TaskbarVisibility
        {
            get 
            {
                return _taskbarVisibility;
            }
            set 
            {
                if (_taskbarVisibility != value)
                {
                    _taskbarVisibility = value;
                    SetTaskbarChange();
                }
            }
        }
        /// <summary>
        /// 源数据初始化
        /// </summary>
        /// <param name="e"></param>
        protected override void OnSourceInitialized(EventArgs e)
        {
            base.OnSourceInitialized(e);
            HwndSource hwndSource = PresentationSource.FromVisual(this) as HwndSource;
            if (hwndSource != null)
            {
                hwndSource.AddHook(new HwndSourceHook(this.WndProc));
                _handle = hwndSource.Handle;
            }
        }
        /// <summary>
        /// 消息截获
        /// </summary>
        /// <param name="hwnd"></param>
        /// <param name="msg"></param>
        /// <param name="wParam"></param>
        /// <param name="lParam"></param>
        /// <param name="handled"></param>
        /// <returns></returns>
        protected virtual IntPtr WndProc(IntPtr hwnd, int msg, IntPtr wParam, IntPtr lParam, ref bool handled)
        {
            switch (msg)
            {
                #region[窗体大小修改]
                case WM_NCHITTEST:
                    this.mousePoint.X = (lParam.ToInt32() & 0xFFFF);
                    this.mousePoint.Y = (lParam.ToInt32() >> 16);
                    double left = this.WindowState == System.Windows.WindowState.Maximized ? 0 : this.Left;
                    double top = this.WindowState == System.Windows.WindowState.Maximized ? 0 : this.Top;
                    // 窗口左上角  
                    if (this.mousePoint.Y - this.Top <= this.agWidth
                       && this.mousePoint.X - left <= this.agWidth)
                    {
                        handled = true;
                        return new IntPtr((int)HitTest.HTTOPLEFT);
                    }
                    // 窗口左下角      
                    else if (this.ActualHeight + top - this.mousePoint.Y <= this.agWidth
                       && this.mousePoint.X - left <= this.agWidth)
                    {
                        handled = true;
                        return new IntPtr((int)HitTest.HTBOTTOMLEFT);
                    }
                    // 窗口右上角  
                    else if (this.mousePoint.Y - top <= this.agWidth
                       && this.ActualWidth + left - this.mousePoint.X <= this.agWidth)
                    {
                        handled = true;
                        return new IntPtr((int)HitTest.HTTOPRIGHT);
                    }
                    // 窗口右下角  
                    else if (this.ActualWidth + left - this.mousePoint.X <= this.agWidth
                       && this.ActualHeight + top - this.mousePoint.Y <= this.agWidth)
                    {
                        handled = true;
                        return new IntPtr((int)HitTest.HTBOTTOMRIGHT);
                    }
                    // 窗口左侧  
                    else if (this.mousePoint.X - left <= this.bThickness)
                    {
                        handled = true;
                        return new IntPtr((int)HitTest.HTLEFT);
                    }
                    // 窗口右侧  
                    else if (this.ActualWidth + left - this.mousePoint.X <= this.bThickness)
                    {
                        handled = true;
                        return new IntPtr((int)HitTest.HTRIGHT);
                    }
                    // 窗口上方  
                    else if (this.mousePoint.Y - top <= this.bThickness)
                    {
                        handled = true;
                        return new IntPtr((int)HitTest.HTTOP);
                    }
                    // 窗口下方  
                    else if (this.ActualHeight + top - this.mousePoint.Y <= this.bThickness)
                    {
                        handled = true;
                        return new IntPtr((int)HitTest.HTBOTTOM);
                    }
                    else 
                    {
                        return IntPtr.Zero;
                        //handled = true;
                        //return new IntPtr((int)HitTest.HTCAPTION);
                    }
                #endregion
                #region[窗体最大化控制]
                case WM_GETMINMAXINFO:
                    WMGetMinMaxInfo(hwnd, lParam);
                    handled = true;
                    break;
                #endregion
            }
            return IntPtr.Zero;
        }
        /// <summary>
        /// 控制窗体最大化
        /// </summary>
        /// <param name="hwnd"></param>
        /// <param name="lParam"></param>
        protected virtual 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;
                if (TaskbarVisibility == System.Windows.Visibility.Visible)
                {
                    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);
                }
                else
                {
                    mmi.ptMaxPosition.x = 0;
                    mmi.ptMaxPosition.y = 0;
                    mmi.ptMaxSize.x = rcMonitorArea.right;
                    mmi.ptMaxSize.y = rcMonitorArea.bottom;
                }
            }
            Marshal.StructureToPtr(mmi, lParam, true);
        }
        /// <summary>
        /// 设置修改任务栏变更
        /// </summary>
        private void SetTaskbarChange()
        {
            WindowState state = this.WindowState;
            this.Opacity = 0;
            this.WindowState = System.Windows.WindowState.Minimized;
            this.WindowState = state;
            this.Opacity = 1;
        }
        /// <summary>
        /// 窗体阴影半径修改
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void ShadowRadiusChanged()
        {
            ControlTemplate template = (ControlTemplate)this.Resources["WindowTemplate"];
            if (template == null) return;
            Grid grid = (Grid)template.FindName("ClientGrid", this);
            if (grid == null) return;
            if (this.WindowState != System.Windows.WindowState.Maximized)
                grid.Margin = new Thickness(10);
            else
                grid.Margin = new Thickness(0);
            if (this.Opacity == 0)
                this.Opacity = 1;
        }
        /// <summary>
        /// 初始化
        /// </summary>
        private void Initialize()
        {
            this.Opacity = 0;
            this.Loaded += (sender, e) => InitializeEvent();
            this.ContentRendered += (sender, e) => ShadowRadiusChanged();
            this.SizeChanged += (sender, e) => ShadowRadiusChanged();
        }
        /// <summary>
        /// 初始化事件
        /// </summary>
        private void InitializeEvent()
        {
            ResourceDictionary resource = new ResourceDictionary();
            resource.Source = new Uri(@"pack://application:,,,/DepthView;component/View/Styles/WindowStyle.xaml", UriKind.RelativeOrAbsolute);
            this.Resources.MergedDictionaries.Add(resource);
            this.Style = (Style)this.Resources["WindowStyleKey"];
        }

        private const int WM_SYSCOMMAND = 0x112;
        private const int WM_GETMINMAXINFO = 0x0024;
        private const int SC_CLOSE = 0xF060;
        private const int SC_MINIMIZE = 0xF020;
        private const int SC_MAXIMIZE = 0xF030;
        private const int WM_NCHITTEST = 0x0084;
        private readonly int agWidth = 12; //拐角宽度  
        private readonly int bThickness = 4; // 边框宽度  
        private Point mousePoint = new Point(); //鼠标坐标 
        private Visibility _taskbarVisibility;
        private IntPtr _handle;

        [DllImport("user32.dll")]
        internal static extern bool MoveWindow(IntPtr hWnd, int X, int Y, int nWidth, int nHeight, bool bRepaint);
        [DllImport("User32.dll", EntryPoint = "SendMessage")]
        internal static extern IntPtr SendMessage(IntPtr hWnd, int msg, IntPtr wParam, IntPtr lParam);
        [DllImport("user32")]
        internal static extern bool GetMonitorInfo(IntPtr hMonitor, MONITORINFO lpmi);
        [DllImport("User32")]
        internal static extern IntPtr MonitorFromWindow(IntPtr handle, int flags);
        [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;
        }
        /// <summary>
        /// 矩形
        /// </summary>
        [StructLayout(LayoutKind.Sequential, Pack = 0)]
        public struct RECT
        {
            /// <summary>
            /// 左边界坐标
            /// </summary>
            public int left;
            /// <summary>
            /// 上边界坐标
            /// </summary>
            public int top;
            /// <summary>
            /// 右边界坐标
            /// </summary>
            public int right;
            /// <summary>
            /// 下边界坐标
            /// </summary>
            public int bottom;
        }
        /// <summary>
        /// 窗体大小信息
        /// </summary>
        [StructLayout(LayoutKind.Sequential)]
        public struct MINMAXINFO
        {
            public POINT ptReserved;
            public POINT ptMaxSize;
            public POINT ptMaxPosition;
            public POINT ptMinTrackSize;
            public POINT ptMaxTrackSize;
        };
        /// <summary>
        /// POINT aka POINTAPI
        /// </summary>
        [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;
            }
        }
        /// <summary>
        /// 鼠标点击信息
        /// </summary>
        public enum HitTest : int
        {
            HTERROR = -2,
            HTTRANSPARENT = -1,
            HTNOWHERE = 0,
            HTCLIENT = 1,
            HTCAPTION = 2,
            HTSYSMENU = 3,
            HTGROWBOX = 4,
            HTSIZE = HTGROWBOX,
            HTMENU = 5,
            HTHSCROLL = 6,
            HTVSCROLL = 7,
            HTMINBUTTON = 8,
            HTMAXBUTTON = 9,
            HTLEFT = 10,
            HTRIGHT = 11,
            HTTOP = 12,
            HTTOPLEFT = 13,
            HTTOPRIGHT = 14,
            HTBOTTOM = 15,
            HTBOTTOMLEFT = 16,
            HTBOTTOMRIGHT = 17,
            HTBORDER = 18,
            HTREDUCE = HTMINBUTTON,
            HTZOOM = HTMAXBUTTON,
            HTSIZEFIRST = HTLEFT,
            HTSIZELAST = HTBOTTOMRIGHT,
            HTOBJECT = 19,
            HTCLOSE = 20,
            HTHELP = 21,
        }
    }

Xaml：

    <ControlTemplate x:Key="WindowTemplate" TargetType="{x:Type Window}">
        <Grid x:Name="ClientGrid" Margin="10">
            <Border Background="{x:Null}" BorderBrush="{TemplateBinding Background}" BorderThickness="2" CornerRadius="3">
                <Border.Effect>
                    <DropShadowEffect x:Name="shadow" BlurRadius="10" ShadowDepth="0"/>
                </Border.Effect>
            </Border>
            <Border Background="{x:Null}"  
                          BorderBrush="{TemplateBinding BorderBrush}"  
                          BorderThickness="{TemplateBinding BorderThickness}"  
                          Padding="{TemplateBinding Margin}"  
                          SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"  
                          CornerRadius="3">
                <ContentPresenter />
            </Border>
        </Grid>
    </ControlTemplate>
    <Style x:Key="WindowStyleKey" TargetType="{x:Type Window}">
        <Setter Property="Template" Value="{DynamicResource ResourceKey=WindowTemplate}"></Setter>
    </Style>

有一个问题就是全屏是否显示任务栏，目前是采用最小化后最大化，来触发WndProc，这个应该可以改进，后期再看看。