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在WPF中使用CefSharp嵌入浏览器

日常开发中，我们需要将一些Web页面嵌入到桌面客户端软件中。下面我们使用CefSharp嵌入浏览器来实现。

首先先介绍一下CefSharp嵌入式浏览器，它是基于Google浏览器的一个组件，我们可以在WPF/WinForm客户端软件中使用它。CefSharp的代码托管在GitHub上，.NET (WPF and Windows Forms) bindings for the Chromium Embedded Framework。

目前最新版本的CefSharp是41.0版本，如果你的客户端软件需要支持WIN XP操作系统，建议使用CefSharp.Wpf 1.25.7及之前的版本。可以从Nuget上获取到具体的内容。在新版本的CefSharp中，已经取消了对WIN XP系统的支持。

具体的实现：(首先引用CefSharp.dll,CefSharp.Wpf.dll 另外将icudt.dll,libcef.dll这两个Dll放置在bin/Debug或者bin/Release目录下)

先创建一个UserControl，并继承IRequestHandler接口，代码如下：

UI:

<UserControl x:Class="EmbeddedWebBrowserSolution.WebPageViewer"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
             xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
             xmlns:local="clr-namespace:EmbeddedWebBrowserSolution"
             xmlns:uc="clr-namespace:EmbeddedWebBrowserSolution"
             mc:Ignorable="d"
             d:DesignHeight="300" d:DesignWidth="300">
    <Grid x:Name="MainGrid">
        <uc:MaskLoading x:Name="maskLoading"/>
    </Grid>
</UserControl>

public partial class WebPageViewer : UserControl, IRequestHandler
    {
        private WebView _view;
 
        public WebPageViewer(string url)
        {
            InitializeComponent();
 
            CEF.Initialize(new Settings { LogSeverity = LogSeverity.Disable, PackLoadingDisabled = true });
 
            BrowserSettings browserSetting = new BrowserSettings { ApplicationCacheDisabled = true, PageCacheDisabled = true };
 
            _view = new WebView(string.Empty, browserSetting)
            {
                Address = url,
                RequestHandler = this,
                Background = Brushes.White
            };
 
            _view.LoadCompleted += _view_LoadCompleted;
 
            MainGrid.Children.Insert(0, _view);
        }
 
        private void _view_LoadCompleted(object sender, LoadCompletedEventArgs url)
        {
            Dispatcher.BeginInvoke(new Action(() => 
            {
                maskLoading.Visibility = Visibility.Collapsed;
            }));
        }
 
        public void View(string url)
        {
            if(_view.IsBrowserInitialized)
            {
                _view.Visibility = Visibility.Hidden;
 
                maskLoading.Visibility = Visibility.Visible;
 
                _view.Load(url);
            }
        }
 
        #region IRequestHandler
        public bool GetAuthCredentials(IWebBrowser browser, bool isProxy, string host, int port, string realm, string scheme, ref string username, ref string password)
        {
            return false;
        }
 
        public bool GetDownloadHandler(IWebBrowser browser, string mimeType, string fileName, long contentLength, ref IDownloadHandler handler)
        {
            return true;
        }
 
        public bool OnBeforeBrowse(IWebBrowser browser, IRequest request, NavigationType naigationvType, bool isRedirect)
        {
            return false;
        }
 
        public bool OnBeforeResourceLoad(IWebBrowser browser, IRequestResponse requestResponse)
        {
            return false;
        }
 
        public void OnResourceResponse(IWebBrowser browser, string url, int status, string statusText, string mimeType, WebHeaderCollection headers)
        {
             
        }
        #endregion
    }

下一步，在MainWindow上来承载，

UI:

<Grid>
      <DockPanel>
          <StackPanel DockPanel.Dock="Top" Orientation="Horizontal">
              <TextBlock Text="Address:" Margin="5"/>
              <TextBox x:Name="txtAddress" Width="350" Margin="5"/>
              <Button Content="Go" Margin="5" Click="OnGoClick" IsDefault="True"/>
          </StackPanel>
 
          <Grid x:Name="MainGrid">
               
          </Grid>
      </DockPanel>
  </Grid>

private void OnGoClick(object sender, RoutedEventArgs e)
        {
            string url = txtAddress.Text;
 
            if (!string.IsNullOrWhiteSpace(url))
            {
                WebPageViewer viewer = new WebPageViewer(url);
                MainGrid.Children.Insert(0,viewer);
            }
        }

注意，需要将工程Platform Target设置为X86。

运行效果：

到这里，一个使用CefSharp来承载Web页面的例子就算完成了。

相比于WPF内置的WebBrowser，CefSharp在处理JS回掉时，比WebBrowser方便很多。请看下面的例子：

我们有这样一个HTML页面：

<!DOCTYPE html>
<html>
<head>
    <title></title>
    <meta charset="utf-8" />
    <script type="text/javascript">
        function callback()
        {
            callbackObj.showMessage('message from js');
        }
    </script>
</head>
<body>
    <input type="button" value="Click" onclick="callback()" ID="Button">
</body>
</html>

增加一个类，叫做：CallbackObjectForJs

public class CallbackObjectForJs
 {
     public void showMessage(string msg)
     {
         MessageBox.Show(msg);
     }
 }

注意这个方法的名称必须小写。

改造一下WebPageViewer类，在构造后WebView之后，注册一个JS对象，

//...
      public WebPageViewer(string url)
      {
          InitializeComponent();
 
          CEF.Initialize(new Settings { LogSeverity = LogSeverity.Disable, PackLoadingDisabled = true });
 
          BrowserSettings browserSetting = new BrowserSettings { ApplicationCacheDisabled = true, PageCacheDisabled = true };
 
          _view = new WebView(string.Empty, browserSetting)
          {
              Address = url,
              RequestHandler = this,
              Background = Brushes.White
          };
 
          _view.RegisterJsObject("callbackObj", new CallbackObjectForJs());
 
          _view.LoadCompleted += _view_LoadCompleted;
 
          MainGrid.Children.Insert(0, _view);
      }   
   //...