我可以将WPF窗口覆盖在另一个窗口之上吗？

Question

我有一个WPF窗口,其中包含一个WindowsFormsHost元素.我需要在这个元素之上绘制东西,但是WindowsFormsHost它的本质意味着它始终位于绘图堆的顶部.由于我无法在WindowsFormsHost组件顶部的同一个WPF窗口中绘制,我可以在其上覆盖另一个窗口吗？

我已经初步尝试了这个,但是我遇到了一些问题:

1)我无法阻止主窗口和覆盖窗口之间的其他应用程序的窗口.

2)当我按Alt-Tab时,覆盖窗口出现在窗口列表中,这非常难看.

基本上我需要一个"子窗口"的概念,并且所有意图和目的的窗口都显示为另一个窗口的一部分.UserControls对我来说不起作用,因为它总是WindowsFormsHost会在它上面绘制.

有任何想法吗？

---

更新[2011年5月23日10:13]

谢谢你们的回答.

我已经尝试过这种ChildWindow方法,而且WindowsFormsHost元素仍然是最重要的.据我了解,只有一个真正的窗口可以在a上面绘制WindowsFormsHost,同一个窗口中的任何东西都会在下面WindowsFormsHost.

用的元素WindowsFormsHost仍然会在一个WinForms组件画,他们总是画在上面,这似乎非流通...

我想我正在寻找的是一种方法来停靠外部窗口作为主窗口的一部分.在Mac上,有一个真正的"儿童窗口"的概念,我正在寻找类似的东西.

Answer 1

我通过使用Popup而不是透明来解决这个问题Window

更新

我最后得到了一个Popup我称之为子类的子类AirspacePopup.

是什么AirspacePopup呢

• 跟着它PlacementTarget.
• 不总是在顶部,而是相对于放置Window它的位置.这个解决方案来自Chris Cavanagh的博客.
• 允许移动到"屏幕外".这是通过在孩子离开屏幕时剪切Popup并设置Margin其子项的负片来实现的.该解决方案来自这个StackOverflow的职位由里克Sladkey

这里是一个例子AirspacePopup是用来绘制一个Ellipse上的顶部WebBrowser控制(这实际上是一个WinForms控制),但它会与任何工作一样好WindowsFormsHost.

<Grid>
    <local:AirspacePopup PlacementTarget="{Binding ElementName=webBrowser}"
                         FollowPlacementTarget="True"
                         AllowOutsideScreenPlacement="True"
                         ParentWindow="{Binding RelativeSource={RelativeSource AncestorType={x:Type Window}}}"
                         IsOpen="True"
                         AllowsTransparency="True"
                         Placement="Center"
                         Width="{Binding ElementName=googleBrowser, Path=ActualWidth}"
                         Height="{Binding ElementName=googleBrowser, Path=ActualHeight}">
        <Grid>
            <Ellipse Width="100" Height="100" Fill="Green" Margin="100"/>
        </Grid>
    </local:AirspacePopup>
    <WebBrowser Name="webBrowser" Loaded="WebBrowser_Loaded"/>
</Grid>

简单的代码背后导航..

public partial class MainWindow : Window
{
    public MainWindow()
    {
        InitializeComponent();
    }

    private void WebBrowser_Loaded(object sender, RoutedEventArgs e)
    {
        WebBrowser webbrowser = sender as WebBrowser;
        webbrowser.Navigate("http://www.stackoverflow.com");
    }
}

AirspacePopup

using System;
using System.ComponentModel;
using System.Diagnostics;
using System.Runtime.InteropServices;
using System.Windows;
using System.Windows.Controls.Primitives;
using System.Windows.Input;
using System.Windows.Interop;

public class AirspacePopup : Popup
{
    public static readonly DependencyProperty IsTopmostProperty =
        DependencyProperty.Register("IsTopmost",
                                    typeof(bool),
                                    typeof(AirspacePopup),
                                    new FrameworkPropertyMetadata(false, OnIsTopmostChanged));

    public static readonly DependencyProperty FollowPlacementTargetProperty =
        DependencyProperty.RegisterAttached("FollowPlacementTarget",
                                            typeof(bool),
                                            typeof(AirspacePopup),
                                            new UIPropertyMetadata(false));

    public static readonly DependencyProperty AllowOutsideScreenPlacementProperty =
        DependencyProperty.RegisterAttached("AllowOutsideScreenPlacement",
                                            typeof(bool),
                                            typeof(AirspacePopup),
                                            new UIPropertyMetadata(false));

    public static readonly DependencyProperty ParentWindowProperty =
        DependencyProperty.RegisterAttached("ParentWindow",
                                            typeof(Window),
                                            typeof(AirspacePopup),
                                            new UIPropertyMetadata(null, ParentWindowPropertyChanged));

    private static void OnIsTopmostChanged(DependencyObject source, DependencyPropertyChangedEventArgs e)
    {
        AirspacePopup airspacePopup = source as AirspacePopup;
        airspacePopup.SetTopmostState(airspacePopup.IsTopmost);
    }

    private static void ParentWindowPropertyChanged(DependencyObject source, DependencyPropertyChangedEventArgs e)
    {
        AirspacePopup airspacePopup = source as AirspacePopup;
        airspacePopup.ParentWindowChanged();
    }

    private bool? m_appliedTopMost;
    private bool m_alreadyLoaded;
    private Window m_parentWindow;

    public AirspacePopup()
    {
        Loaded += OnPopupLoaded;
        Unloaded += OnPopupUnloaded;

        DependencyPropertyDescriptor descriptor = DependencyPropertyDescriptor.FromProperty(PlacementTargetProperty, typeof(AirspacePopup));
        descriptor.AddValueChanged(this, PlacementTargetChanged);
    }

    public bool IsTopmost
    {
        get { return (bool)GetValue(IsTopmostProperty); }
        set { SetValue(IsTopmostProperty, value); }
    }
    public bool FollowPlacementTarget
    {
        get { return (bool)GetValue(FollowPlacementTargetProperty); }
        set { SetValue(FollowPlacementTargetProperty, value); }
    }
    public bool AllowOutsideScreenPlacement
    {
        get { return (bool)GetValue(AllowOutsideScreenPlacementProperty); }
        set { SetValue(AllowOutsideScreenPlacementProperty, value); }
    }
    public Window ParentWindow
    {
        get { return (Window)GetValue(ParentWindowProperty); }
        set { SetValue(ParentWindowProperty, value); }
    }

    private void ParentWindowChanged()
    {
        if (ParentWindow != null)
        {
            ParentWindow.LocationChanged += (sender, e2) =>
            {
                UpdatePopupPosition();
            };
            ParentWindow.SizeChanged += (sender, e2) =>
            {
                UpdatePopupPosition();
            };
        }
    }
    private void PlacementTargetChanged(object sender, EventArgs e)
    {
        FrameworkElement placementTarget = this.PlacementTarget as FrameworkElement;
        if (placementTarget != null)
        {
            placementTarget.SizeChanged += (sender2, e2) =>
            {
                UpdatePopupPosition();
            };
        }
    }

    private void UpdatePopupPosition()
    {
        FrameworkElement placementTarget = this.PlacementTarget as FrameworkElement;
        FrameworkElement child = this.Child as FrameworkElement;

        if (PresentationSource.FromVisual(placementTarget) != null &&
            AllowOutsideScreenPlacement == true)
        {
            double leftOffset = CutLeft(placementTarget);
            double topOffset = CutTop(placementTarget);
            double rightOffset = CutRight(placementTarget);
            double bottomOffset = CutBottom(placementTarget);
            Debug.WriteLine(bottomOffset);
            this.Width = Math.Max(0, Math.Min(leftOffset, rightOffset) + placementTarget.ActualWidth);
            this.Height = Math.Max(0, Math.Min(topOffset, bottomOffset) + placementTarget.ActualHeight);

            if (child != null)
            {
                child.Margin = new Thickness(leftOffset, topOffset, rightOffset, bottomOffset);
            }
        }
        if (FollowPlacementTarget == true)
        {
            this.HorizontalOffset += 0.01;
            this.HorizontalOffset -= 0.01;
        }
    }
    private double CutLeft(FrameworkElement placementTarget)
    {
        Point point = placementTarget.PointToScreen(new Point(0, placementTarget.ActualWidth));
        return Math.Min(0, point.X);
    }
    private double CutTop(FrameworkElement placementTarget)
    {
        Point point = placementTarget.PointToScreen(new Point(placementTarget.ActualHeight, 0));
        return Math.Min(0, point.Y);
    }
    private double CutRight(FrameworkElement placementTarget)
    {
        Point point = placementTarget.PointToScreen(new Point(0, placementTarget.ActualWidth));
        point.X += placementTarget.ActualWidth;
        return Math.Min(0, SystemParameters.VirtualScreenWidth - (Math.Max(SystemParameters.VirtualScreenWidth, point.X)));
    }
    private double CutBottom(FrameworkElement placementTarget)
    {
        Point point = placementTarget.PointToScreen(new Point(placementTarget.ActualHeight, 0));
        point.Y += placementTarget.ActualHeight;
        return Math.Min(0, SystemParameters.VirtualScreenHeight - (Math.Max(SystemParameters.VirtualScreenHeight, point.Y)));
    }

    private void OnPopupLoaded(object sender, RoutedEventArgs e)
    {
        if (m_alreadyLoaded) 
            return;

        m_alreadyLoaded = true;

        if (Child != null)
        {
            Child.AddHandler(PreviewMouseLeftButtonDownEvent, new MouseButtonEventHandler(OnChildPreviewMouseLeftButtonDown), true);
        }

        m_parentWindow = Window.GetWindow(this);

        if (m_parentWindow == null) 
            return;

        m_parentWindow.Activated += OnParentWindowActivated;
        m_parentWindow.Deactivated += OnParentWindowDeactivated;
    }

    private void OnPopupUnloaded(object sender, RoutedEventArgs e)
    {
        if (m_parentWindow == null)
            return;
        m_parentWindow.Activated -= OnParentWindowActivated;
        m_parentWindow.Deactivated -= OnParentWindowDeactivated;
    }

    private void OnParentWindowActivated(object sender, EventArgs e)
    {
        SetTopmostState(true);
    }

    private void OnParentWindowDeactivated(object sender, EventArgs e)
    {
        if (IsTopmost == false)
        {
            SetTopmostState(IsTopmost);
        }
    }

    private void OnChildPreviewMouseLeftButtonDown(object sender, MouseButtonEventArgs e)
    {
        SetTopmostState(true);
        if (!m_parentWindow.IsActive && IsTopmost == false)
        {
            m_parentWindow.Activate();
        }
    }

    protected override void OnOpened(EventArgs e)
    {
        SetTopmostState(IsTopmost);
        base.OnOpened(e);
    }

    private void SetTopmostState(bool isTop)
    {
        // Don’t apply state if it’s the same as incoming state
        if (m_appliedTopMost.HasValue && m_appliedTopMost == isTop)
        {
            return;
        }

        if (Child == null) 
            return;

        var hwndSource = (PresentationSource.FromVisual(Child)) as HwndSource;

        if (hwndSource == null) 
            return;
        var hwnd = hwndSource.Handle;

        RECT rect;

        if (!GetWindowRect(hwnd, out rect)) 
            return;

        Debug.WriteLine("setting z-order " + isTop);

        if (isTop)
        {
            SetWindowPos(hwnd, HWND_TOPMOST, rect.Left, rect.Top, (int)Width, (int)Height, TOPMOST_FLAGS);
        }
        else
        {
            // Z-Order would only get refreshed/reflected if clicking the
            // the titlebar (as opposed to other parts of the external
            // window) unless I first set the popup to HWND_BOTTOM
            // then HWND_TOP before HWND_NOTOPMOST
            SetWindowPos(hwnd, HWND_BOTTOM, rect.Left, rect.Top, (int)Width, (int)Height, TOPMOST_FLAGS);
            SetWindowPos(hwnd, HWND_TOP, rect.Left, rect.Top, (int)Width, (int)Height, TOPMOST_FLAGS);
            SetWindowPos(hwnd, HWND_NOTOPMOST, rect.Left, rect.Top, (int)Width, (int)Height, TOPMOST_FLAGS);
        }

        m_appliedTopMost = isTop;
    }

    #region P/Invoke imports & definitions
    #pragma warning disable 1591 //Xml-doc
    #pragma warning disable 169 //Never used-warning
    // ReSharper disable InconsistentNaming
    // Imports etc. with their naming rules

    [StructLayout(LayoutKind.Sequential)]
    public struct RECT

    {
        public int Left;
        public int Top;
        public int Right;
        public int Bottom;
    }

    [DllImport("user32.dll")]
    [return: MarshalAs(UnmanagedType.Bool)]
    private static extern bool GetWindowRect(IntPtr hWnd, out RECT lpRect);

    [DllImport("user32.dll")]
    private static extern bool SetWindowPos(IntPtr hWnd, IntPtr hWndInsertAfter, int X,
    int Y, int cx, int cy, uint uFlags);

    static readonly IntPtr HWND_TOPMOST = new IntPtr(-1);
    static readonly IntPtr HWND_NOTOPMOST = new IntPtr(-2);
    static readonly IntPtr HWND_TOP = new IntPtr(0);
    static readonly IntPtr HWND_BOTTOM = new IntPtr(1);

    private const UInt32 SWP_NOSIZE = 0x0001;
    const UInt32 SWP_NOMOVE = 0x0002;
    const UInt32 SWP_NOZORDER = 0x0004;
    const UInt32 SWP_NOREDRAW = 0x0008;
    const UInt32 SWP_NOACTIVATE = 0x0010;

    const UInt32 SWP_FRAMECHANGED = 0x0020; /* The frame changed: send WM_NCCALCSIZE */
    const UInt32 SWP_SHOWWINDOW = 0x0040;
    const UInt32 SWP_HIDEWINDOW = 0x0080;
    const UInt32 SWP_NOCOPYBITS = 0x0100;
    const UInt32 SWP_NOOWNERZORDER = 0x0200; /* Don’t do owner Z ordering */
    const UInt32 SWP_NOSENDCHANGING = 0x0400; /* Don’t send WM_WINDOWPOSCHANGING */

    const UInt32 TOPMOST_FLAGS = 
        SWP_NOACTIVATE | SWP_NOOWNERZORDER | SWP_NOSIZE | SWP_NOMOVE | SWP_NOREDRAW | SWP_NOSENDCHANGING;

    // ReSharper restore InconsistentNaming
    #pragma warning restore 1591
    #pragma warning restore 169
    #endregion
}

Answer 2

您可以在WindowsFormsHost. 因此，您可以有一个子元素，该子元素应该位于托管元素中其他内容的顶部。