在C＃中创建COM / ActiveXObject的，从JScript中使用，具有简单的事件 [英] Create COM/ActiveXObject in C#, use from JScript, with simple event

问题描述

我想创建在C＃中的COM对象，并通过IDispatch接口从JScript中使用它。这部分是非常简单的。

I'd like to create a COM object in C#, and use it via IDispatch from JScript. That part is pretty simple.

我也想实现COM对象简单的回调，类似于XmlHttpRequest对象是在浏览器中使用的暴露事件。这种模式允许JavaScript附加事件处理程序是这样的：

I also want to implement simple callbacks on the COM object, similar to the event exposed by the XmlHttpRequest object that is usable in a browser. That model allows Javascript to attach event handlers like this:

var xmlhttp = new ActiveXObject("MSXML.XMLHTTP"); 
xmlhttp.onReadyStateChange = function() {
  ...
};

我希望我的客户端JScript代码看起来是这样的：

I want my client-side JScript code to look like this:

var myObject = new ActiveXObject("MyObject.ProgId");
myObject.onMyCustomEvent = function(..args here..) { 
   ...
};

什么是C＃代码是什么样子？我想一般情况下 - 我希望能够通过参数回给Javascript新生力量。

What does the C# code look like? I'd like the general case - I'd like to be able to pass arguments back to the Javascript fn.

我见过的我怎样才能让用C＃编写ActiveX控件提高JavaScript事件点击时<？ / A>，但答案有看起来很复杂，实施和复杂的使用。

I've seen How can I make an ActiveX control written with C# raise events in JavaScript when clicked? , but the answers there look really complicated to implement, and complicated to use.

从的这篇文章，似乎XMLHttpRequest的事件并不COM事件。在的onreadystatechange 是类型的属性的IDispatch 。当客户端脚本设置该属性给一个函数，JScript的老帅它作为一个IDispatch对象。

From this article, it seems that XMLHttpRequest events are not COM events. The onreadystatechange is a property of type IDispatch. When script clients set that property to a function, JScript marshals it as an IDispatch object.

这仍然是唯一的问题是然后再从C＃调用了IDispatch。

The only problem that remains is then to invoke the IDispatch from C#.

推荐答案

由于它的COM，通过定义界面启动。让我们保持它的简单。

Since it's COM, start by defining an interface. Let's keep it simple.

[Guid("a5ee0756-0cbb-4cf1-9a9c-509407d5eed6")]
[InterfaceType(ComInterfaceType.InterfaceIsIDispatch)]
public interface IGreet
{
    [DispId(1)]
    string Hello(string name);

    [DispId(2)]
    Object onHello { get; set; }
}

然后，执行：

Then, the implementation:

[ProgId("Cheeso.Greet")]
[ComVisible(true)]
[Guid("bebcfaff-d2f4-4447-ac9f-91bf63b770d8")]
[ClassInterface(ClassInterfaceType.None)]
public partial class Greet : IGreet
{
    public Object onHello { get; set; }

    public String Hello(string name)
    {
        var r = FireEvent();
        return "Why, Hello, " + name + "!!!" + r;
    }
}

主要的窍门是 FireEvent 方法。这为我工作。

The main trick is the FireEvent method. This worked for me.

    private string FireEvent()
    {
        if (onHello == null) return " (N/A)";
        onHello
            .GetType()
            .InvokeMember
            ("",
             BindingFlags.InvokeMethod,
             null,
             onHello,
             new object [] {});

        return "ok";
    }

编译所有的在一起，regasm注册它：

Compile that all together, register it with regasm:

%NET64%\regasm.exe Cheeso.Greet.dll /register /codebase

...然后用它从JScript中是这样的：

...And then use it from JScript like this:

var greet = new ActiveXObject("Cheeso.Greet"), response;
greet.onHello = function() {
    WScript.Echo("onHello (Javascript) invoked.");
};
response = greet.Hello("Fred");
WScript.Echo("response: " + response);

它的工作原理。

It works.

您也可以从VBScript中调用它：

You can also call it from VBScript:

Sub onHello ()
    WScript.Echo("onHello (VBScript) invoked.")
End Sub

Dim greet
Set greet = WScript.CreateObject("Cheeso.Greet")
greet.onHello = GetRef("onHello")
Dim response
response = greet.Hello("Louise")
WScript.Echo("response: " &  response)

---

要从C＃参数传递回的JScript与这种做法，我觉得对象需要是IDispatch接口，当然你可以发送编组为字符串，整数，等等这是封送如你所愿回到简单的值。

---

To pass parameters back from C# to JScript with this approach, I think objects need to be IDispatch, but of course you can send back simple values marshaled as string, int, and so on which are marshaled as you would expect.

例如，修改C＃代码来引用发回它本身，而数42

For example, modify the C# code to send back a reference to itself, and the number 42.

        onHello
            .GetType()
            .InvokeMember
            ("",
             BindingFlags.InvokeMethod,
             null,
             onHello,
             new object [] { this, 42 });

然后，你可以在像这样的JScript：

Then, you can get that in jscript like so:

greet.onHello = function(arg, num) {
    WScript.Echo("onHello (Javascript) invoked.");
    WScript.Echo("  num = " + num + "  stat=" + arg.status);
};

或者VBScript中，像这样：

Or in VBScript like so:

Sub onHello (obj, num)
    WScript.Echo("onHello (VBScript) invoked. status=" & obj.status )
    WScript.Echo("  num= " & num)
End Sub

注意：你可以定义你的JScript事件处理程序函数接受比由C＃对象调用事件时，发送较少ARGS。根据我的经验，你需要设计VBScript中的事件处理程序，明确接受正确的参数个数。

NB: You can define your jscript event handler function to accept fewer args than are sent by the C# object when invoking the "event". In my experience you need to design the event handler in VBScript to explicitly accept the correct number of arguments.

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