WPF 中 WindowsFormsHost 之 AirspacePanel

        项目中使用WPF开发客户端，系统需要内嵌C++开发的控件，在WPF中内嵌Winfrom或者Win32K控件都需要 包裹在 WindowsFormsHost 中，很顺利的将控件显示出来。如下：

 

     后续开发中，需要在当前页面，开发一个弹框功能。如下：

      So ! ! !

      弹出框被遮挡了，查了资料在  https://github.com/chris84948/AirspaceFixer 找到其中一种解决方案，该方案是在弹出框之前设置 WindowsFormsHost  显示一张截图替代，关闭弹出框之后替换回来。

     具体实现如下：

                                                                                     

 internal class AirspacePanel : System.Windows.Controls.ContentControl
    {
        public static readonly DependencyProperty FixAirspaceProperty =
            DependencyProperty.Register("FixAirspace",
                                        typeof(bool),
                                        typeof(AirspacePanel),
                                        new FrameworkPropertyMetadata(false, new PropertyChangedCallback(OnFixAirspaceChanged)));

        public bool FixAirspace
        {
            get { return (bool)GetValue(FixAirspaceProperty); }
            set { SetValue(FixAirspaceProperty, value); }
        }


        private System.Windows.Controls.Image _airspaceScreenshot;
        private System.Windows.Controls.ContentControl _airspaceContent;
        private float _scalingFactor;

        static AirspacePanel()
        {
            DefaultStyleKeyProperty.OverrideMetadata(typeof(AirspacePanel), new FrameworkPropertyMetadata(typeof(AirspacePanel)));
        }

        public AirspacePanel()
        {
            Loaded += (_, __) => GetScalingFactor();
        }

        public override void OnApplyTemplate()
        {
            base.OnApplyTemplate();

            _airspaceContent = GetTemplateChild("PART_AirspaceContent") as ContentControl;
            _airspaceScreenshot = GetTemplateChild("PART_AirspaceScreenshot") as System.Windows.Controls.Image;
        }

        private static void OnFixAirspaceChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            var panel = d as AirspacePanel;
            


            if (panel == null || panel.ActualWidth == 0 || panel.ActualHeight == 0 || PresentationSource.FromVisual(panel) == null)
                return;

            if ((bool)e.NewValue)
            {
               
                panel._airspaceContent.Visibility = Visibility.Hidden;
                panel._airspaceScreenshot.Visibility = Visibility.Visible;
            }
            else
            {
                panel._airspaceContent.Visibility = Visibility.Visible;
                panel._airspaceScreenshot.Visibility = Visibility.Hidden;
                panel._airspaceScreenshot.Source = null;
            }
        }

  
        private void CreateScreenshotFromContent()
        {
            System.Windows.Point upperLeftPoint = _airspaceContent.PointToScreen(new System.Windows.Point(0, 0));
            var bounds = new System.Drawing.Rectangle((int)(upperLeftPoint.X * _scalingFactor),
                                                      (int)(upperLeftPoint.Y * _scalingFactor),
                                                      (int)(_airspaceContent.RenderSize.Width * _scalingFactor),
                                                      (int)(_airspaceContent.RenderSize.Height * _scalingFactor));

            using (var bitmap = new System.Drawing.Bitmap((int)bounds.Width, (int)bounds.Height))
            {
                using (var g = System.Drawing.Graphics.FromImage(bitmap))
                {
                    g.CopyFromScreen(new System.Drawing.Point(bounds.Left, bounds.Top),
                                     System.Drawing.Point.Empty,
                                     new System.Drawing.Size((int)bounds.Width, (int)bounds.Height));
                }

                _airspaceScreenshot.Source = GetImageSourceFromBitmap(bitmap);
            }
        }

  
        [DllImport("gdi32.dll")]
        static extern int GetDeviceCaps(IntPtr hdc, int nIndex);
        private void GetScalingFactor()
        {
            var g = System.Drawing.Graphics.FromHwnd(IntPtr.Zero);
            IntPtr desktop = g.GetHdc();
            int LogicalScreenHeight = GetDeviceCaps(desktop, 10);
            int PhysicalScreenHeight = GetDeviceCaps(desktop, 117);

            float ScreenScalingFactor = (float)PhysicalScreenHeight / (float)LogicalScreenHeight;

            _scalingFactor = ScreenScalingFactor; // 1.25 = 125%
        }

        public ImageSource GetImageSourceFromBitmap(System.Drawing.Bitmap bitmap)
        {
            using (var memory = new MemoryStream())
            {
                bitmap.Save(memory,ImageFormat.Png);
                memory.Position = 0;
                System.Windows.Media.Imaging.BitmapImage bitmapImage = new BitmapImage();
                bitmapImage.BeginInit();
                bitmapImage.StreamSource = memory;
                bitmapImage.CacheOption = BitmapCacheOption.OnLoad;
                bitmapImage.EndInit();
                return bitmapImage;
            }
        }
    }

 

         

 

 

      设置样式：

  <Style TargetType="{x:Type dwayneneed:AirspacePanel}">
            <Setter Property="Template">
                <Setter.Value>
                    <ControlTemplate TargetType="{x:Type dwayneneed:AirspacePanel}">

                        <Grid HorizontalAlignment="{TemplateBinding HorizontalAlignment}"
                          VerticalAlignment="{TemplateBinding VerticalAlignment}">
                            <Image x:Name="PART_AirspaceScreenshot"
                               Visibility="Hidden" />

                            <ContentControl x:Name="PART_AirspaceContent"
                                        Content="{TemplateBinding Content}" />
                        </Grid>

                    </ControlTemplate>
                </Setter.Value>
            </Setter>
        </Style>

 

       包裹 WindowsFormsHost 

       

            <AirspacePanel x:Name="airspacePanel"  FixAirspace="{Binding FixAirspace}">

                  <WindowsFormsHost x:Name="host"  Visibility="Visible" />

             </AirspacePanel>

 

     弹窗之前设置 

  FixAirspace=true；

  弹窗之后设置

  FixAirspace=false；