揭露索引像属性COM [英] Exposing indexer like properties to COM

问题描述

我在现有的COM接口。我wan't创建公开了新的界面，COM（具有新的GUID）.NET程序集，但接口的结构必须一致。

如何创建一个.NET类（C＃），公开此接口？

  [
 ODL，
 UUID（1ED4C594-DDD7-402F-90DE-7F85D65560C4），
隐藏，
了oleautomation 
] 
接口_IFlashPhase：{IUnknown的
 
 [propget子] 
 HRESULT _stdcall组件名（
 [中]总之我，
 [出来，RETVAL] BSTR * PVAL）; 
 [propput] 
 HRESULT _stdcall组件名（
 [中]总之我，
 [中] BSTR PVAL）; 
 [propget子] 
 HRESULT _stdcall ComponentMolePercent（
 [中]总之我，
 [出来，RETVAL]双* PVAL）; 
 [propput] 
 HRESULT _stdcall ComponentMolePercent（
 [中]总之我，
 [中]双PVAL）; 
 [propget子] 
 HRESULT _stdcall ComponentFugacity（
 [中]总之我，
 [出来，RETVAL]双* PVAL）; 
 [propput] 
 HRESULT _stdcall ComponentFugacity（
 [中]总之我，
 [中]双PVAL）; 
 
}; 
  

解决方案

您IDL是无效的，这是一个接口使用[了oleautomation]应归功于从IDispatch接口派生，而不是IUnknown的。我给你需要对它们进行修改，以得到你适当的声明和提示。

您不能在C＃中声明索引属性，C＃团队拒绝执行。第4版拥有了在COM类型库中声明，但仍不允许自己宣布这些索引属性的支持。解决方法是使用VB.NET语言，它有没有关于它的疑虑。一个VB.NET类库项目添加到您的解决方案。使它看起来类似于这样：

 进口System.Runtime.InteropServices 
 
命名空间喃喃
 
<标记有ComVisible特性（真）> _ 
<的Guid（2352FDD4-F7C9-443a-BC3F-3EE230EF6C1B）> _ 
< InterfaceType（ComInterfaceType.InterfaceIsDual）GT; _ 
公用接口的IExample 
< D​​ISPID（0）GT; _ 
属性索引（BYVAL指数为整数）作为整数
< D​​ISPID（1）> _ 
房产SomeProperty（BYVAL指数为整数）作为字符串
端接口
 
端命名空间
  

请注意使用<的; DISPID> ，DISPID 0是特殊的，它是一个接口的默认属性。这相当于在C＃语言的索引器。

所有你需要VB.NET的是声明，你仍然可以写的实施的在C＃语言的接口。项目+添加引用，项目选项卡，然后选择VB.NET工程。使它看起来类似于这样：

 使用系统;使用System.Runtime.InteropServices 
; 
 
命名空间喃喃{
 [标记有​​ComVisible特性（真）] 
 [的Guid（8B72CE6C-511F-456e-B71B-ED3B3A09A03C）] 
 [ClassInterface（ClassInterfaceType。无）] 
耻骨类实现：ClassLibrary2.Mumble.IExample {
公众诠释get_Indexer（INT指数）{
收益指数; 
} 
公共无效set_Indexer（INT指数，int值）{
} 
 
公共字符串get_SomeProperty（INT指数）{
返回index.ToString（ ）; 
} 
 
公共无效set_SomeProperty（INT指数，字符串值）{
} 
} 
} 
  

您需要在的两个的VB.NET的和C＃程序集生成类型库运行Tlbexp.exe。 C＃的一个具有实现包括VB.NET之一。

要获得接口从IUnknown的，而不是IDispatch接口派生，编辑的接口声明。取出DISPID属性和使用ComInterfaceType.InterfaceIsUnknown

I have in existing COM-interface. I wan't to create a .net assembly that exposes a new interface as COM (with a new GUID), but the structure of the interface needs to be the same.

How can i create a .net class (C#) that exposes this interface?

[
  odl,
  uuid(1ED4C594-DDD7-402F-90DE-7F85D65560C4),
  hidden,
  oleautomation
]
interface _IFlashPhase : IUnknown {

    [propget]
    HRESULT _stdcall ComponentName(
                    [in] short i, 
                    [out, retval] BSTR* pVal);
    [propput]
    HRESULT _stdcall ComponentName(
                    [in] short i, 
                    [in] BSTR pVal);
    [propget]
    HRESULT _stdcall ComponentMolePercent(
                    [in] short i, 
                    [out, retval] double* pVal);
    [propput]
    HRESULT _stdcall ComponentMolePercent(
                    [in] short i, 
                    [in] double pVal);
    [propget]
    HRESULT _stdcall ComponentFugacity(
                    [in] short i, 
                    [out, retval] double* pVal);
    [propput]
    HRESULT _stdcall ComponentFugacity(
                    [in] short i, 
                    [in] double pVal);

};

解决方案

Your IDL isn't valid, an interface that is attributed with [oleautomation] should derive from IDispatch, not IUnknown. I'll give the proper declarations and hint where you need to modify them to get yours.

You cannot declare indexed properties in C#, the C# team refuses to implement them. Version 4 has support for indexed properties that are declared in a COM type library but still doesn't allow declaring them yourself. The workaround is to use the VB.NET language, it has no qualms about it. Add a VB.NET class library project to your solution. Make it look similar to this:

Imports System.Runtime.InteropServices

Namespace Mumble

    <ComVisible(True)> _
    <Guid("2352FDD4-F7C9-443a-BC3F-3EE230EF6C1B")> _
    <InterfaceType(ComInterfaceType.InterfaceIsDual)> _
    Public Interface IExample
        <DispId(0)> _
        Property Indexer(ByVal index As Integer) As Integer
        <DispId(1)> _
        Property SomeProperty(ByVal index As Integer) As String
    End Interface

End Namespace

Note the use of <DispId>, dispid 0 is special, it is the default property of an interface. This corresponds to the indexer in the C# language.

All you need VB.NET for is the declaration, you can still write the implementation of the interface in the C# language. Project + Add Reference, Projects tab and select the VB.NET project. Make it look similar to this:

using System;
using System.Runtime.InteropServices;

namespace Mumble {
    [ComVisible(true)]
    [Guid("8B72CE6C-511F-456e-B71B-ED3B3A09A03C")]
    [ClassInterface(ClassInterfaceType.None)]
    pubic class Implementation : ClassLibrary2.Mumble.IExample {
        public int get_Indexer(int index) {
            return index;
        }
        public void set_Indexer(int index, int Value) {
        }

        public string get_SomeProperty(int index) {
            return index.ToString();
        }

        public void set_SomeProperty(int index, string Value) {
        }
    }
}

You need to run Tlbexp.exe on both the VB.NET and the C# assembly to generate the type libraries. The C# one with the implementation includes the VB.NET one.

To get the interface to derive from IUnknown instead of IDispatch, edit the interface declaration. Remove the DispId attributes and use ComInterfaceType.InterfaceIsUnknown

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