WPF 窗口位于最大化状态的顶部/左侧任务栏下方

Question

我正在开发 WPF 应用程序，当WindowStyle=None和WindowState = WindowState.Maximized 应用程序位于顶部或左侧任务栏下方时，我遇到了问题。

当任务栏位于底部或右侧时，一切正常。

我知道窗口的Left 和Top 属性，但是在Maximized 状态下它们被忽略了。

还有Microsoft.Windows.Shell.WindowСhrome 可以拖动、双击以最大化和恢复、捕捉和取消捕捉。 （需要添加为dll引用）

我想实现我的应用程序不会隐藏或进入任务栏，并且可以与WindowСhrome 提供的行为一起正常工作。

MainWindow.xaml

    <Window x:Class="WpfAppTestFullScreen.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        mc:Ignorable="d"
        WindowStyle="None"
        Title="MainWindow" Height="350" Width="525"
        Left="100" Top="100">
    <WindowChrome.WindowChrome>
        <WindowChrome CaptionHeight="{Binding ActualHeight,ElementName=topBarGrid}"/>
    </WindowChrome.WindowChrome>
    <Grid x:Name="mainGrid" Background="Yellow">
        <Grid.RowDefinitions>
            <RowDefinition Height="Auto"></RowDefinition>
            <RowDefinition Height="*"></RowDefinition>
        </Grid.RowDefinitions>
        <Grid x:Name="topBarGrid" Grid.Row="0" >
            <Border BorderBrush="Black" BorderThickness="1" >
                <DockPanel x:Name="panelForWindowControls"
                           VerticalAlignment="Stretch"
                           DockPanel.Dock="Right"
                           LastChildFill="False"
                           >
                    <Button Name="buttonExit"
                            Width="43" Height="28"
                            Margin="0" Click="buttonExit_Click"
                            DockPanel.Dock="Right" Content="x"
                            WindowChrome.IsHitTestVisibleInChrome="True"
                     />
                    <Button Name="buttonMax"
                            Width="43" Height="28"
                            Margin="0" Click="buttonMax_Click"
                            DockPanel.Dock="Right" Content="[]"
                            WindowChrome.IsHitTestVisibleInChrome="True"
                            />

                    <Button Name="buttonMin" 
                            Width="43" Height="28"
                            Margin="0" Click="buttonMin_Click"
                            DockPanel.Dock="Right" Content="_"
                            WindowChrome.IsHitTestVisibleInChrome="True"
                            />
                </DockPanel>
            </Border>
        </Grid>
        <Grid x:Name="bodyGrid"  Grid.Row="1">
            <Button Content="FullScreen" x:Name="FullScreenButton" 
                Height="50" Width="200" 
                HorizontalAlignment="Center"  VerticalAlignment="Center"
                Click="FullScreenButton_Click" />
        </Grid>
    </Grid>
</Window>

MainWindow.xaml.cs

    using System.Windows;


namespace WpfAppTestFullScreen
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
            MaxHeight = SystemParameters.MaximizedPrimaryScreenHeight;
            MaxWidth = SystemParameters.MaximizedPrimaryScreenWidth;
        }


        private void FullScreenButton_Click(object sender, RoutedEventArgs e)
        {
            if (WindowState == WindowState.Maximized)
            {
                WindowState = WindowState.Normal;
            }
            else
            {
                WindowState = WindowState.Maximized;
            }
        }

        private void buttonMax_Click(object sender, RoutedEventArgs e)
        {
            if (WindowState == WindowState.Maximized)
            {
                WindowState = WindowState.Normal;
            }
            else
            {
                WindowState = WindowState.Maximized;
            }
        }

        private void buttonMin_Click(object sender, RoutedEventArgs e)
        {
            WindowState = (WindowState == WindowState.Minimized) ? WindowState.Normal : WindowState.Minimized;
        }
        private void buttonExit_Click(object sender, RoutedEventArgs e)
        {

        }

    }
}

这里是问题的截图：

Answer 1

更好的方法是使用 User32.dll 中的几个本机方法
（取自this blog post）

它是如何工作的：

• 为 WindowMessages (WindowProc) 添加一个挂钩，以便您可以从系统接收窗口消息。

  每个窗口都有一个关联的窗口过程——一个处理发送或发布到类的所有窗口的所有消息的函数。窗口外观和行为的所有方面都取决于窗口过程对这些消息的响应。

• 您将收到通知 (0x24 = WM_GETMINMAXINFO) 窗口大小即将更改

  当窗口的大小或位置即将改变时发送到窗口。应用程序可以使用此消息来覆盖窗口的默认最大化大小和位置，或者其默认的最小或最大跟踪大小。

• 您将获得窗口当前所在的监视器 (MonitorFromWindow) 并更新边界。

  应用程序可以通过设置此结构的成员来覆盖默认值。

• 系统会处理剩下的事情。

因此，无论窗口如何调整大小（拖动到屏幕顶部、windows 键 + 箭头、最大化按钮等），它都将保持在工作区的边界内。

本机方法和类型：
_{（只需将此类复制到您的项目中）}

public static class Native
{

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

    [DllImport("user32")]
    internal static extern IntPtr MonitorFromWindow(IntPtr handle, int flags);

    public static void WmGetMinMaxInfo(IntPtr hwnd, IntPtr lParam, int minWidth, int minHeight)
    {
        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;
        IntPtr monitor = Native.MonitorFromWindow(hwnd, MONITOR_DEFAULTTONEAREST);

        if (monitor != IntPtr.Zero)
        {

            Native.MONITORINFO monitorInfo = new Native.MONITORINFO();
            Native.GetMonitorInfo(monitor, monitorInfo);
            Native.RECT rcWorkArea = monitorInfo.rcWork;
            Native.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);
            mmi.ptMinTrackSize.x = minWidth;
            mmi.ptMinTrackSize.y = minHeight;
        }

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


    /// <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;
        }
    }

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

    /// <summary>
    /// </summary>
    [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> Win32 </summary>
    [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);
        }
    }
}

你的窗口：

public partial class MainWindow : Window
{
    public MainWindow()
    {
        SourceInitialized += Window_SourceInitialized;

        InitializeComponent();
    }

    void Window_SourceInitialized(object sender, EventArgs e)
    {
        IntPtr handle = new WindowInteropHelper(this).Handle;
        HwndSource.FromHwnd(handle)?.AddHook(WindowProc);
    }

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

        return (IntPtr)0;
    }

    private void FullScreenButton_Click(object sender, RoutedEventArgs e)
    {
        WindowState = WindowState == WindowState.Maximized ? WindowState.Normal : WindowState.Maximized;
    }

    private void buttonMax_Click(object sender, RoutedEventArgs e)
    {
        WindowState = WindowState == WindowState.Maximized ? WindowState.Normal : WindowState.Maximized;
    }

    private void buttonMin_Click(object sender, RoutedEventArgs e)
    {
        WindowState = WindowState == WindowState.Minimized ? WindowState.Normal : WindowState.Minimized;
    }

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