在C＃中的ComVisible类中的接口继承 [英] Interface inheritance in ComVisible classes in C#

问题描述

从w / cscript无法访问继承的属性（P1）。

Inherited property (P1) is not accessable from w/cscript.

类结构如下所示：

[ComVisible]
public interface IA 
{
     string P1{get;} 
} 

[ComVisible]
public interface IB : IA
{
    string P2{get;} 
}

[ComVisible]
public abstract class Base : IA
{
    public string P1{get{return "somestring";}}
}   

[ComVisible]
public class Concrete : Base, IB
{
   public string P2{get{return "P2somestring";}}
}

js文件中的客户端代码： p>

Client code in js file :

try{
var obj = new ActiveXObject("Concrete");
WshShell.Popup(obj.P1); //<-- displays empty string
}catch(e)
{
WshShell.Popup(e.description);
}

如果我将属性P1添加到接口IB，一切正常，
但是什么是继承点呢？或者我在这里做了一些真的错误？

if i add property P1 to interface IB, everything works fine, but whats the point of inheritance then? Or am i doing here something really wrong?

推荐答案

我偷了这个从 COM Interop：不暴露给COM的基类属性链接C＃暴露给COM - 接口继承

特别是该网站上的MVP声明：

In particular the MVP on that site states:

在COM接口中可以相互继承。然而，.NET实现暴露.NET接口到COM不支持继承。因此，您必须将基本接口中的任何接口成员复制到派生接口...在构建暴露的COM接口时，Interop代码不会查看基本接口类型。

In COM interfaces can inherit from one another. However the .NET implementation that exposes the .NET interface to COM does not support inheritance. Therefore you must replicate any interface members in a base interface to the derived interface... The interop code does not look at base interface types when building the exposed COM interface.

它建议一些解决方法，例如从两个接口继承，或实现一个本地TLB（在IDL中编写界面并使用MIDL编译它 - 在vis studio中应该有这样的项目） 。

It does suggest some workarounds, such as inheriting from both interfaces, or implementing a 'native' TLB (write the inteface in IDL and compile it with MIDL - there should be projects for this in vis studio).

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