WPF与Javascript交互

风中Robin 2012-06-22

展开全文

今天在WPF中使用WebBrowser的InvokeScript方法与Javascript交互时遇到若干问题，记录如下：

　　使用[ComVisible(true)] 标记公开给脚本访问的对象

　　调用InvokeScript方法一定要在WebBrowser LoadCompleted后调用

　　使用 function 申明后台需要调用的方法

　　返回COMException表明调用脚本函数未找到

　　HTML:demo.htm

<!DOCTYPE>
<html>
<head>
    <meta charset="utf-8" />
    <title></title>
</head>
<body>
    <input type="button" onclick="window.external.say('this is from htm');return false;" value="调用后方法" />
    <div id="msg"></div>
    <script type="text/javascript">
        (function (window) {
            var searcher = {
                showmsg: function (msg) {
                    alert(msg);
                }
            };
            window.searcher = searcher;
        })(window);

        function showmsg(msg) {
            searcher.showmsg(msg);
        }
    </script>
</body>
</html>

　　WPF:MainWindow.xam

l<Grid >
        <Grid.RowDefinitions>
            <RowDefinition Height="50"/>
            <RowDefinition Height="*"/>
        </Grid.RowDefinitions>
        <Border BorderBrush="BlueViolet" BorderThickness="0,0,0,1">
            <StackPanel Orientation="Horizontal">
                <Button x:Name="btn1" Width="100" Height="40" Click="btn1_Click" Content="加载页面" VerticalAlignment="Center" Margin="10,0"></Button>
                <Button x:Name="btn2" Width="100" Height="40" Click="btn2_Click" Content="调用脚本" VerticalAlignment="Center"></Button>
            </StackPanel>
        </Border>
        <WebBrowser x:Name="webBrowser" Grid.Row="1"></WebBrowser>
</Grid>

　　后台代码如下：

/// <summary>
    /// Web.xaml 的交互逻辑
    /// </summary>
    public partial class Web : Window
    {
        public Action webHandler;

        public Web()
        {
            InitializeComponent();
            this.webBrowser.ObjectForScripting = new ScriptObject(this);
            this.webBrowser.LoadCompleted += new System.Windows.Navigation.LoadCompletedEventHandler(webBrowser_LoadCompleted);
        }

        void webBrowser_LoadCompleted(object sender, System.Windows.Navigation.NavigationEventArgs e)
        {
            if (this.webHandler != null)
            {
                this.webHandler();
                this.webHandler = null;
            }
        }

        private void btn1_Click(object sender, RoutedEventArgs e)
        {
            this.webHandler = () =>
            {
                this.webBrowser.InvokeScript("showmsg", new object[] { "{'center':{'lng':12.232,'lat':13.232},'zoom':14}" });
            };
            string htmlfile = System.IO.Path.Combine("file:///", System.Environment.CurrentDirectory, "Resources/demo.htm");
            this.webBrowser.Navigate(new Uri(htmlfile, UriKind.RelativeOrAbsolute));
        }

        private void btn2_Click(object sender, RoutedEventArgs e)
        {
            this.webBrowser.InvokeScript("showmsg", new object[] { "{'center':{'lng':12.232,'lat':13.232},'zoom':14}" });
        }
    }

    [ComVisible(true)]
    public class ScriptObject
    {
        private Window instance;
        public ScriptObject(Window instance)
        {
            this.instance = instance;
        }

        public void say(string msg)
        {
            MessageBox.Show(msg, "来自服务端的消息", MessageBoxButton.OK, MessageBoxImage.Information);
        }
    }

　　从cs调用js失败的情况(一直没有找到问题的原因):

　　cs:

　　InvokeScript("searcher.showmsg", new object[] { "hello" })

　　js: