将 DWM 缩略图添加为 WPF 控件子项

Posted 2023-03-29

【中文标题】将 DWM 缩略图添加为 WPF 控件子项

【英文标题】：adding DWM Thumbnails as WPF control child

【发布时间】：2017-09-13 07:49:17

【问题描述】：

我使用 DWM 缩略图创建窗口选择器，但我想将此缩略图添加为 WPF StackPanl 的子项，我该怎么做？ 因此，在这段代码中，我有一个名为“b”的网格，我想为其添加 App Thumbnail 作为子项。

这是代码：

     #region dwmapi.dll imports

    [DllImport("dwmapi.dll", PreserveSig = false)]
    private static extern bool DwmIsCompositionEnabled();

    [DllImport("dwmapi.dll")]
    private static extern int DwmExtendFrameIntoClientArea(IntPtr hWnd, ref MARGINS pMargins);

    [StructLayout(LayoutKind.Sequential)]
    struct MARGINS
    
        public int Left;
        public int Right;
        public int Top;
        public int Bottom;

        public void ExtendToWholeClientArea()
        
            this.Left = -1;
            this.Right = -1;
            this.Top = -1;
            this.Bottom = -1;
        
    

    [DllImport("dwmapi.dll")]
    private static extern int DwmRegisterThumbnail(IntPtr dest, IntPtr src, out IntPtr thumb);

    [DllImport("dwmapi.dll")]
    private static extern int DwmUnregisterThumbnail(IntPtr thumb);

    [DllImport("dwmapi.dll")]
    private static extern int DwmQueryThumbnailSourceSize(IntPtr thumb, out PSIZE size);

    [StructLayout(LayoutKind.Sequential)]
    private struct PSIZE
    
        public int x;
        public int y;
    

    [DllImport("dwmapi.dll")]
    private static extern int DwmUpdateThumbnailProperties(IntPtr hThumb, ref DWM_THUMBNAIL_PROPERTIES props);

    [StructLayout(LayoutKind.Sequential)]
    private struct DWM_THUMBNAIL_PROPERTIES
    
        public int dwFlags;
        public RECT rcDestination;
        public RECT rcSource;
        public byte opacity;
        public bool fVisible;
        public bool fSourceClientAreaOnly;
    

    [StructLayout(LayoutKind.Sequential)]
    private struct RECT
    
        public RECT(int left, int top, int right, int bottom)
        
            Left = left;
            Top = top;
            Right = right;
            Bottom = bottom;
        

        public int Left;
        public int Top;
        public int Right;
        public int Bottom;
    

    private static readonly int DWM_TNP_VISIBLE = 0x8;
    private static readonly int DWM_TNP_RECTDESTINATION = 0x1;
    private static readonly int DWM_TNP_SOURCECLIENTAREAONLY = 0x00000010;

    #endregion

 private void DrawThumbnail(WindowInfo win, int thumbnailIndex) IntPtr thumbnail = win.Thumbnail;
        if (thumbnail != IntPtr.Zero)
            DwmUnregisterThumbnail(thumbnail);
        int hResult = DwmRegisterThumbnail(mainWindowHandle, win.HWnd, out thumbnail);
        if (hResult == 0)
        
            PSIZE size;
            DwmQueryThumbnailSourceSize(thumbnail, out size);

            DWM_THUMBNAIL_PROPERTIES props = new DWM_THUMBNAIL_PROPERTIES();
            props.dwFlags = DWM_TNP_VISIBLE | DWM_TNP_RECTDESTINATION | DWM_TNP_SOURCECLIENTAREAONLY;
            props.fVisible = true;
            props.fSourceClientAreaOnly = true;


             Grid b = new Grid()  Height = ThumbnailSize+20, Width = ThumbnailSize+(WindowLeftOffset), Background = (SolidColorBrush)(new BrushConverter().ConvertFrom("#55D3E6EE")), Tag = UnSelectedTag ,VerticalAlignment=VerticalAlignment.Stretch,HorizontalAlignment=HorizontalAlignment.Stretch;
            b.MouseLeftButtonDown += B_MouseLeftButtonDown;

            //Set the region where the live preview will be drawn ======> I want to add this region as a child for "b" grid 
            int left = (thumbnailIndex % MaxThumbnails) * (ThumbnailSize + ThumbnailSpacing)+ WindowLeftOffset;
            int top = (int)(thumbnailIndex / MaxThumbnails) * (ThumbnailSize + ThumbnailSpacing) + WindowTopOffset;
            int right = left + ThumbnailSize;
            int bottom = top + ThumbnailSize;

            props.rcDestination = new RECT(left, top, right, bottom);


            Border bor = new Border()   BorderThickness = new Thickness(1), BorderBrush = (SolidColorBrush)(new BrushConverter().ConvertFrom("#550863A2")), CornerRadius= new CornerRadius(2) ;
            bor.Child = b;
            bor.SetValue(Canvas.LeftProperty, (double)(((drowingIndex % MaxThumbnails) * (ThumbnailSize + ThumbnailSpacing))+WindowLeftOffset - (WindowLeftOffset/2)-1));
            bor.SetValue(Canvas.TopProperty, Math.Floor((double)(drowingIndex / MaxThumbnails)) * (ThumbnailSize + ThumbnailSpacing));
            canvas.Children.Add(bor);

            drowingIndex++;
            previweStackPanels.Add(b);

            //Center the live preview
            if (size.x < size.y)
            
                double ScaleFactor = ThumbnailSize / (double)size.y;
                int scaledX = (int)(size.x * ScaleFactor);
                int xOffset = (ThumbnailSize - scaledX) / 2;
                props.rcDestination.Left += xOffset;
                props.rcDestination.Right -= xOffset;
            
            if (size.y < size.x)
            
                double ScaleFactor = ThumbnailSize / (double)size.x;
                int scaledY = (int)(size.y * ScaleFactor);
                int yOffset = (ThumbnailSize - scaledY) / 2;
                props.rcDestination.Top += yOffset;
                props.rcDestination.Bottom -= yOffset;
            

            DwmUpdateThumbnailProperties(thumbnail, ref props);
        
    

【参考方案1】：

Panel（例如Grid 和StackPanel）有一个Children 集合，您可以将UIElements 添加到其中：

previweStackPanels.Children.Add(b);

请注意，除了UIElement 对象之外，您不能将任何其他对象添加到Panel。

这意味着您不能将RECT 添加到Grid，因为RECT 不是UIElement。不过，您可以添加 System.Windows.Shapes.Rectangle：

【讨论】：

不，我想将这个 Rectangle props.rcDestination = new RECT(left, top, right, bottom); 添加为一个孩子 .. previweStackPanels 只是所有 StackPanels 的列表

作为什么的孩子？

of b Grid .. 所以我有运行窗口的缩略图，我想将此窗口的缩略图添加为子窗口或 Grid b 的内容@

我想你应该再读一遍我的答案。您可以仅将 UIElements 添加到 Grid 的 Children 集合中，并且由于 RECT 不是 UI 元素，因此您不能将此元素添加到 Grid。不过，您可以添加 System.Windows.Shapes.Rectangle。