WPF内嵌WebBrowser不显示问题

WPF项目中需要在 Windows上做出透明效果，加上透明效果后，莫名其妙的windows上内嵌的WebBrowser就消失不见了。

windows的样式代码如下：

<Style x:Key="faq_window" TargetType="Window">
        <Setter Property="AllowsTransparency" Value="true"/>
        <Setter Property="Background" Value="Transparent"/>
        <Setter Property="FontFamily" Value="Microsoft YaHei Light"/>
        <Setter Property="FontSize" Value="14"/>
        <Setter Property="ResizeMode" Value="NoResize"/>
        <Setter Property="WindowStyle" Value="None"/>
        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate TargetType="{x:Type Window}">
                    <Grid Margin="8">
                        <Border BorderBrush="#6F666666" BorderThickness="1" Background="White" 
        SnapsToDevicePixels="True">
                            <Border.Effect>
                                <DropShadowEffect ShadowDepth="0" BlurRadius="10"/>
                            </Border.Effect>
                            <ContentPresenter />
                        </Border>
                    </Grid>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>

 

网上找了各种资料，发现：

若设置窗体为AllowsTransparency="True"，WindowStyle="None"，内嵌的WebBrowser就无法显示了，但它加载的网页内容还能正常交互。

所以，这是个无法解决的问题?网友给了一种解决方法，经过测试是可以的，这里记录下。

整体思路是这样的：我们自己创建一个窗体，然后初始化的时候，我们去寻找原窗体，计算窗体的大小（宽，高），和位置，然后将我们创建的窗体放到原来的webbrowser上。

1.创建文件：WebBrowserOverlay.xaml

<Window x:Class="operateToolWPF.Controls.WebBrowserOverlay"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        WindowStyle="None" ShowInTaskbar="False" ResizeMode="NoResize" Background="Transparent" Opacity="0"  >
    <WebBrowser Name="_wb">

    </WebBrowser>
</Window>  

2.创建文件：WebBrowserOverlay.xaml.cs

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Runtime.InteropServices;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Interop;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Shapes;


namespace myWPF.Controls
{
    /// <summary>
    /// WebBrowserOverlay.xaml 的交互逻辑
    /// </summary>
    public partial class WebBrowserOverlay : Window
    {
        FrameworkElement _placementTarget;


        public WebBrowser WebBrowser { get { return this._wb; } }

        
        public WebBrowserOverlay(FrameworkElement placementTarget)
        {
            InitializeComponent();

            //_wb = WebBrowser;
            _placementTarget = placementTarget;
            Window owner = Window.GetWindow(placementTarget);
            Debug.Assert(owner != null);
            //Owner = owner;
            //owner.SizeChanged += delegate { OnSizeLocationChanged(); };  
            owner.LocationChanged += delegate { OnSizeLocationChanged(); };
            _placementTarget.SizeChanged += delegate { OnSizeLocationChanged(); };


            if (owner.IsVisible)
            {
                Owner = owner;
                //OnSizeLocationChanged();
                Show();
            }
            else
                owner.IsVisibleChanged += delegate
                {
                    if (owner.IsVisible)
                    {
                        Owner = owner;
                        Show();
                    }
                };


            //owner.LayoutUpdated += new EventHandler(OnOwnerLayoutUpdated);  
        }


        protected override void OnClosing(System.ComponentModel.CancelEventArgs e)
        {
            base.OnClosing(e);
            if (!e.Cancel)
                // Delayed call to avoid crash due to Window bug.  
                Dispatcher.BeginInvoke((Action)delegate
                {
                    Owner.Close();
                });
        }


        void OnSizeLocationChanged()
        {
            if (Owner != null)
            {
                Point offset = _placementTarget.TranslatePoint(new Point(), Owner);
                Point size = new Point(_placementTarget.ActualWidth, _placementTarget.ActualHeight);
                HwndSource hwndSource = (HwndSource)HwndSource.FromVisual(Owner);
                CompositionTarget ct = hwndSource.CompositionTarget;
                offset = ct.TransformToDevice.Transform(offset);
                size = ct.TransformToDevice.Transform(size);


                Win32.POINT screenLocation = new Win32.POINT(offset);
                Win32.ClientToScreen(hwndSource.Handle, ref screenLocation);
                Win32.POINT screenSize = new Win32.POINT(size);

                //问题：(HwndSource)HwndSource.FromVisual(this)为null
                Win32.MoveWindow(((HwndSource)HwndSource.FromVisual(this)).Handle, screenLocation.X, screenLocation.Y, screenSize.X, screenSize.Y, true);
                //Win32.MoveWindow(((HwndSource)HwndSource.FromVisual(WebBrowserOverlay this)).Handle, screenLocation.X, screenLocation.Y, screenSize.X, screenSize.Y, true);
            }
            
        }
    }
    static class Win32
    {
        [StructLayout(LayoutKind.Sequential)]
        public struct POINT
        {
            public int X;
            public int Y;

            public POINT(int x, int y)
            {
                this.X = x;
                this.Y = y;
            }
            public POINT(Point pt)
            {
                X = Convert.ToInt32(pt.X);
                Y = Convert.ToInt32(pt.Y);
            }
        };

        [DllImport("user32.dll")]
        internal static extern bool ClientToScreen(IntPtr hWnd, ref POINT lpPoint);

        [DllImport("user32.dll")]
        internal static extern bool MoveWindow(IntPtr hWnd, int X, int Y, int nWidth, int nHeight, bool bRepaint);
    }
}

3.在你需要使用的xaml中添加下面代码：

<Border x:Name="BdBrowser" Margin="0,30,0,0">
                    <WebBrowser x:Name="show_help" Panel.ZIndex="111" Canvas.Left="0" Canvas.Top="32" Width="610" Height="385" Visibility="Hidden" IsHitTestVisible="False" LoadCompleted="show_help_LoadCompleted" />
                </Border>

4.需要使用的cs文件中添加代码：

var w = new WebBrowserOverlay(this.BdBrowser);
var wb = w.WebBrowser;
var HelpUrl = "http://www.baidu.com";
wb.Navigate(new System.Uri(HelpUrl));