Question

我有COM compnent（dll）ThirdParty定义了界面和一些实现此接口的COM类ThirdPartyObjectClass。我有适当的文件ThirdParty.h和ThirdParty_i.c允许用C ++编译它。
```
   IThirdParty
   {
        HRESULT ComFoo();
   }
```
我使用＆＃34; tlbimp / sysarray＆＃34;构建名为ThirdPartyInterop.dll的interop dll，暴露.Net接口ThirdPartyObject

我编写了新的C＃组件，它引用了ThirdPartyInterop.dll

  using ThirdPartyInterop;
  namespace CsComponent
  {
        public class CsClass
        {
            public void NetFoo( ThirdPartyObject thirdPrty )
            {
                thirdPrty.ComFoo();
            }
        } 
   }

ThirdPartyClass的元词是：

   using System.Runtime.InteropServices;

   namespace ThirdPartyInterop
   {
       [CoClass(typeof(ThirdPartyObjectClass))]
       [Guid("xxxx")]
       public interface ThirdPartyObject : IThirdParty
       {
       }
   }

和

   using System;
   using System.Runtime.InteropServices;

   namespace ThirdPartyInterop
   {
       [TypeLibType(4160)]
       [Guid("yyyy")]
       public interface IThirdParty
       {
           [DispId(1)]
           void ComFoo();
       }
   }

我有一个用托管C ++编写的旧代码。

with the following:

   #include "stdafx.h"
   #pragma managed(push, off)
   #include "ThirdParty_i.c"
   #include "ThirdParty.h"
   #pragma managed(pop)

   void CppFoo( IThirdParty* thirdParty )
   {
       ...
       thirdParty -> ComFoo();
       ...
   }

我需要将其更改为使用我的CsClass：

   #include "stdafx.h"
   #pragma managed(push, off)
   #include "ThirdParty_i.c"
   #include "ThirdParty.h"
   #pragma managed(pop)

   void CppFoo( IThirdParty* thirdParty )
   {
       ...
       //thirdParty -> ComFoo();
       CsComponent::CsClass^ csClass = gcnew CsComponent::CsClass();
       csClass.NetFoo( thirdParty );
       ...
   }

但是这不能编译：错误C2664：＆＃39; CsComponent :: CsClass :: NetFoo＆＃39; ：无法从＆＃39; IThirdParty *＆＃39;转换参数1 to＆＃39; ThirdPartyInterop :: ThirdPartyObject ^＆＃39;

以下实施是可以的：

   #include "stdafx.h"
   #pragma managed(push, off)
   #include "ThirdParty_i.c"
   #include "ThirdParty.h"
   #pragma managed(pop)

   void CppFoo( IThirdParty* thirdParty )
   {
       ...
       //thirdParty -> ComFoo();
       CsComponent::CsClass^ csClass = gcnew CsComponent::CsClass();
       ThirdPartyInterop::ThirdPartyObject^ _thirdParty = gcnew ThirdPartyInterop::ThirdPartyObject();
       //csClass.NetFoo( thirdParty );
       csClass.NetFoo( _thirdParty );
       ...
   }

但我需要使用CppFoo的参数thirdParty。

我的问题是：

如何从给定的IThirdParty *创建ThirdPartyInterop :: ThirdPartyObject？

Answer 1

因为在你的情况下，每个IThirdParty实际上都是一个ThirdPartyObject，你可以使用强制转换。 Hovewer，除了在新的指令中，你不应该使用com对象的具体类型，总是只使用接口。更改您的NetFoo（）方法以将IThirdParty作为参数。

错误C2664 - 需要帮助和澄清

1 个答案: