如何在 Javascript 中连接 C# ActiveX 事件处理程序

Question

利用几个代码片段，我试图将 ActiveX 对象与 Javascript 事件处理程序连接起来。我无法确定为什么没有调用事件处理程序。

Github Repository with project.

更新

通过在 'onLoad' 事件中放置对 SayHello() 的 javascript 调用，我能够触发 ActiveX 事件。现在我正在寻找 C# 调用，以及如何将它挂接到 Javascript.

使用的 ActiveX 对象中

（这可能也依赖于从 IE 的高级选项中启用本地脚本）。

消息续

事件处理程序在 same form as described for this question 中完成。

    <script for="MyObject" event="OnUpdateString(stuff)">
        document.write("<p>" + stuff);
        document.writeln("</p>");
    </script>

利用 MSDN documentation 我创建了一个 WinForms 应用程序，其中包含一个充当 ObjectForScripting 的 WebBrowser 控件（与该问题无关）。此容器调用 ActiveX 事件，但未被 Javascript 处理。我将 C# 表单代码包括在 ActiveX 交互中以使其完整，并允许它成为 ActiveX and/or WebBrowser 控件的未来用户的参考。

此文件旨在与新的 Windows Form 项目一起使用，其中 WebBrowser 控件已添加到主 window.

C#Form1.cs

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Security.Permissions;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using ActiveXObjectSpace;

namespace TestActiveX
{
    [PermissionSet(SecurityAction.Demand, Name = "FullTrust")]
    [System.Runtime.InteropServices.ComVisibleAttribute(true)]
    public partial class Form1 : Form
    {
        MyObject myObject = new MyObject();
        public Form1()
        {
            InitializeComponent();
            Text = "ActiveX Test";

            Load += new EventHandler(Form1_Load);
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            webBrowser1.AllowWebBrowserDrop = false;
            webBrowser1.ObjectForScripting = this;
            webBrowser1.Url = new Uri(@"C:\path\to\TestPage.html");

            // Call ActiveX
            myObject.SayHello("C# Launch");
        }

        public string ControlObject()
        {
            return "<p>Control Object Called.</p>";
        }
    }
}

结合 two other code snippets 的帮助，我创建了一个 ActiveX 对象。如前所述，需要在构建后进行注册。

C#ObjectX.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Runtime.InteropServices;


/// http://blogs.msdn.com/b/asiatech/archive/2011/12/05/how-to-develop-and-deploy-activex-control-in-c.aspx
/// 
///
/// Register with %NET64%\regasm /codebase <full path of dll file>
/// Unregister with %NET64%\regasm /u <full path of dll file>
namespace ActiveXObjectSpace
{

    /// <summary>
    /// Provides the ActiveX event listeners for Javascript.
    /// </summary>
    [Guid("4E250775-61A1-40B1-A57B-C7BBAA25F194"), InterfaceType(ComInterfaceType.InterfaceIsIDispatch)]
    public interface IActiveXEvents
    {
        [DispId(1)]
        void OnUpdateString(string data);
    }

    /// <summary>
    /// Provides properties accessible from Javascript.
    /// </summary>
    [Guid("AAD0731A-E84A-48D7-B5F8-56FF1B7A61D3"), InterfaceType(ComInterfaceType.InterfaceIsIDispatch)]
    public interface IActiveX
    {
        [DispId(10)]
        string CustomProperty { get; set; }
    }

    [ProgId("MyObject")]
    [ComVisible(true)]
    [ClassInterface(ClassInterfaceType.AutoDual)]
    [Guid("7A5D58C7-1C27-4DFF-8C8F-F5876FF94C64")]
    [ComSourceInterfaces(typeof(IActiveXEvents))]
    public class MyObject : IActiveX
    {

        public delegate void OnContextChangeHandler(string data);
        new public event OnContextChangeHandler OnUpdateString;

        // Dummy Method to use when firing the event
        private void MyActiveX_nMouseClick(string index)
        {

        }

        public MyObject()
        {
            // Bind event
            this.OnUpdateString = new OnContextChangeHandler(this.MyActiveX_nMouseClick);
        }

        [ComVisible(true)]
        public string CustomProperty { get; set; }


        [ComVisible(true)]
        public void SayHello(string who)
        {
            OnUpdateString("Calling Callback: " + who);
        }
    }
}

最后是 html 页面，由浏览器或容器加载。它成功加载 ActiveX 对象并包含 OnUpdateString 的事件处理程序。它检查是否可以调用 ActiveX 提供的函数 SayHello 并进行调用。

我希望将 Javascript 和 C# 调用写入文档，但没有写入此类条目。

TestPage.html

<!DOCTYPE html>

<html lang="en" xmlns="http://www.w3.org/1999/xhtml">
<head>
    <title>DemoCSharpActiveX webpage</title>
</head>
<body>
        <script type="text/javascript">
        window.objectLoadFailure = false;
        </script>

        <object id="MyObject" onerror="window.objectLoadFailure = true" classid="clsid:7A5D58C7-1C27-4DFF-8C8F-F5876FF94C64"></object>

        <script for="MyObject" event="OnUpdateString(stuff)">
            document.write("<p>" + stuff);
            document.writeln("</p>");
        </script>


        <script type="text/javascript">
            document.write("<p>Loaded ActiveX Object: " + !window.objectLoadFailure);
            document.writeln("</p>");
            if (typeof window.external.ControlObject !== "undefined") {
                document.write(window.external.ControlObject());
            }


            var obj = document.MyObject;
            if (typeof obj.SayHello !== "undefined") {
                document.writeln("<p>Can Call say hello</p>")
            }
            obj.SayHello("Javascript Load");

        </script>
</body>
</html>

包含页面显示此输出

输出

Loaded ActiveX Object: true

Control Object Called.

Can Call say hello

Answer 1

已更新，只要你可以得到从HTML实例化的<object>（MyObject.object != null), 你的 JavaScript 事件处理程序的最终问题只是你在调用 MyObject.SayHello("Javascript Load")，并替换为<p>Loaded ActiveX Object: ...</p>。到那时，所有原始的 JavaScript 事件处理程序都消失了。

因此，以下工作正常，事件被触发和处理（使用 alert）：

<!DOCTYPE html>
<html>
<head>
    <title>DemoCSharpActiveX webpage</title>
</head>
<body>
    <script type="text/javascript">
        window.objectLoadFailure = false;
    </script>

    <object id="MyObject" onerror="window.objectLoadFailure = true" classid="clsid:7A5D58C7-1C27-4DFF-8C8F-F5876FF94C64"></object>

    <script type="text/javascript" for="MyObject" event="OnUpdateString">
        alert("Hello from event handler");
    </script>

    <script type="text/javascript" for="window" event="onload">
        alert("Hello from window.onload!");
        alert(MyObject.object);
        MyObject.SayHello("Javascript Load");
    </script>
</body>
</html>

要使您的原始逻辑正常工作，您可以直接操作 DOM 而不是使用 document.write。或者，至少在触发和处理 OnUpdateString 之后调用它。

现在我已经看到了完整的源代码，我可以说出这里的一些错误。

您可以在 SayHello 内打断点，因为您从 C# [MyObject myObject = new MyObject()] 创建 MyObject 并从 C# [myObject.SayHello("C# Launch") 调用它].删除它，当您从 JavaScript [obj.SayHello("Javascript Load")].

这会导致另一个问题：<object> 没有成功创建，甚至 none 的 JavaScript 脚本甚至运行，因为您的测试 HTML 文件是从本地文件系统提供的（通过 file:// 协议）。这是一个安全限制。尝试像下面这样更改您的脚本，以查看实际显示的 none 个警报：

<script type="text/javascript" for="window" event="onload">
    alert("Hello from window.onload!");
    alert(MyObject.object) // null! object wasn't created...
    document.write("<p>Loaded ActiveX Object: " + !window.objectLoadFailure);
    document.writeln("</p>");
    if (typeof window.external.ControlObject !== "undefined") {
        document.write(window.external.ControlObject());
    }


    var obj = document.MyObject;
    if (typeof obj.SayHello !== "undefined") {
        document.writeln("<p>Can Call say hello</p>")
    }
    obj.SayHello("Javascript Load");
</script>

有多种修复方法。最简单的可能是使用 "Mark of Web". The hardest one would be to provide a custom implementation of IInternetSecurityManager. I myself would use yet another method - Internet Feature Control - and disable FEATURE_LOCALMACHINE_LOCKDOWN, FEATURE_BLOCK_LMZ_SCRIPT, FEATURE_BLOCK_LMZ_OBJECT keys. You can use following code I adapted from my other related answer:

// static constructor, runs first
static Form1()
{
    SetWebBrowserFeatures();
}

static void SetWebBrowserFeatures()
{
    // don't change the registry if running in-proc inside Visual Studio
    if (LicenseManager.UsageMode != LicenseUsageMode.Runtime)
        return;

    var appName = System.IO.Path.GetFileName(System.Diagnostics.Process.GetCurrentProcess().MainModule.FileName);

    var featureControlRegKey = @"HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main\FeatureControl\";

    Registry.SetValue(featureControlRegKey + "FEATURE_BROWSER_EMULATION",
        appName, GetBrowserEmulationMode(), RegistryValueKind.DWord);

    // enable the features which are "On" for the full Internet Explorer browser

    Registry.SetValue(featureControlRegKey + "FEATURE_ENABLE_CLIPCHILDREN_OPTIMIZATION",
        appName, 1, RegistryValueKind.DWord);

    Registry.SetValue(featureControlRegKey + "FEATURE_AJAX_CONNECTIONEVENTS",
        appName, 1, RegistryValueKind.DWord);

    Registry.SetValue(featureControlRegKey + "FEATURE_GPU_RENDERING",
        appName, 1, RegistryValueKind.DWord);

    Registry.SetValue(featureControlRegKey + "FEATURE_WEBOC_DOCUMENT_ZOOM",
        appName, 1, RegistryValueKind.DWord);

    Registry.SetValue(featureControlRegKey + "FEATURE_NINPUT_LEGACYMODE",
        appName, 0, RegistryValueKind.DWord);

    Registry.SetValue(featureControlRegKey + "FEATURE_LOCALMACHINE_LOCKDOWN",
        appName, 0, RegistryValueKind.DWord);

    Registry.SetValue(featureControlRegKey + "FEATURE_BLOCK_LMZ_SCRIPT",
        appName, 0, RegistryValueKind.DWord);

    Registry.SetValue(featureControlRegKey + "FEATURE_BLOCK_LMZ_OBJECT",
        appName, 0, RegistryValueKind.DWord);
}

static UInt32 GetBrowserEmulationMode()
{
    int browserVersion = 0;
    using (var ieKey = Registry.LocalMachine.OpenSubKey(@"SOFTWARE\Microsoft\Internet Explorer",
        RegistryKeyPermissionCheck.ReadSubTree,
        System.Security.AccessControl.RegistryRights.QueryValues))
    {
        var version = ieKey.GetValue("svcVersion");
        if (null == version)
        {
            version = ieKey.GetValue("Version");
            if (null == version)
                throw new ApplicationException("Microsoft Internet Explorer is required!");
        }
        int.TryParse(version.ToString().Split('.')[0], out browserVersion);
    }

    if (browserVersion < 7)
    {
        throw new ApplicationException("Unsupported version of Microsoft Internet Explorer!");
    }

    UInt32 mode = 11000; // Internet Explorer 11. Webpages containing standards-based !DOCTYPE directives are displayed in IE11 Standards mode. 

    switch (browserVersion)
    {
        case 7:
            mode = 7000; // Webpages containing standards-based !DOCTYPE directives are displayed in IE7 Standards mode. 
            break;
        case 8:
            mode = 8000; // Webpages containing standards-based !DOCTYPE directives are displayed in IE8 mode. 
            break;
        case 9:
            mode = 9000; // Internet Explorer 9. Webpages containing standards-based !DOCTYPE directives are displayed in IE9 mode.                    
            break;
        case 10:
            mode = 10000; // Internet Explorer 10.
            break;
    }

    return mode;
}

现在，您的脚本执行运行，但 <object> 仍然没有创建（alert(MyObject.object) 显示 null）。最后，您需要仅在您自己的 HTML 页面上实施 IObjectSafety interface on your ActiveX object and site-lock 它。如果没有适当的 IObjectSafety，将不会在默认的 IE 安全设置下创建对象。如果没有站点锁定，它可能会成为一个巨大的安全威胁，因为任何恶意脚本都可能在您的应用程序上下文之外创建和使用您的对象。

已更新 以解决评论：

I've updated the project with your provided example, note that I had made a change such that there is a C# button and a Javascript button to fire the event. The JS button works, but C# does not fire. I'm looking for a "Hello from: C# button" alert.

在您的代码中，myObject 实例从 C# 中独占创建和访问：

MyObject myObject = new MyObject();

// ...

private void button1_Click(object sender, EventArgs e)
{
   // Call ActiveX
   myObject.SayHello("C# Button");
}

此实例与您从 HTML 创建的 <object id="MyObject" onerror="window.objectLoadFailure = true" classid="clsid:7A5D58C7-1C27-4DFF-8C8F-F5876FF94C64"></object> 实例无关。它们是两个 独立的 不相关的对象。您的事件处理程序仅适用于后者 <object> 实例。您甚至没有订阅 new MyObject() 实例上的任何事件。

如果我正确理解你的目标，你需要这个：

private void button1_Click(object sender, EventArgs e)
{
    // Call ActiveX
    //myObject.SayHello("C# Button");

    this.webBrowser1.Document.InvokeScript("eval",
        new[] { "MyObject.SayHello('C# Button')" });
}

现在，JavaScript 事件处理程序将被调用，您会看到 "C# Button" 警报。

如何在 Javascript 中连接 C# ActiveX 事件处理程序

How to connect a C# ActiveX event handler in Javascript

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