从C ++中的COM互操作的不叫回来管理对象的方法 [英] Returned managed object method not called from C++ in COM interop
问题描述
这是从我的<一个跟进href="http://stackoverflow.com/questions/19465041/interop-com-isch-interface-marshaling-results-in-accessviotlationexception-on">$p$pvious帖子。阅读该职位的情况下。请注意，这是不严格COM互操作 - 但C ++接口是COM兼容
我试着去实现这个C ++在C＃接口
类IPluginFactory：公共FUnknown
{
虚拟tresult PLUGIN_API createInstance建立（FIDString CID，FIDString独立同分布的，无效** OBJ）= 0;
};
我的C＃code是这样的：
[ComImport]
[的Guid（Interfaces.IPluginFactory）
[InterfaceType（ComInterfaceType.InterfaceIsIUnknown）
公共接口IPluginFactory
{
[preserveSig]
[返回：的MarshalAs（UnmanagedType.Error）
INT32的CreateInstance（[IN] REF的Guid的classId，[在] REF的Guid interfaceId，[的MarshalAs（UnmanagedType.IUnknown），输入，输出]参考对象实例）;
}
的实施分配一个新对象实例的实例参数和返回0（S_OK）。我甚至强制转换为预期的（管理）接口。
实例=（IPluginBase）新PluginBase（）;
返回0;
返回的对象是由该C psented重新$ P $ ++接口：
类IPluginBase：公共FUnknown
{
上市：
虚拟tresult PLUGIN_API初始化（FUnknown *上下文）= 0;
虚拟tresult PLUGIN_API终止（）= 0;
};
看起来像这样在我的C＃实现：
[ComImport]
[的Guid（Interfaces.IPluginBase）
[InterfaceType（ComInterfaceType.InterfaceIsIUnknown）
公共接口IPluginBase
{
[preserveSig]
[返回：的MarshalAs（UnmanagedType.Error）
INT32初始化（[的MarshalAs（UnmanagedType.IUnknown），在]对象上下文）;
[preserveSig]
[返回：的MarshalAs（UnmanagedType.Error）
INT32终止（）;
}
在非托管C ++测试应用程序我写的，我可以成功调用createInstance建立和接受一个非空指针code使用作为IPluginBase *。
的问题是当我尝试调用这个IPluginBase *指针初始化的方法。它从来没有达到管理code（无断点命中 - 其他断点做工精细）和返回code是0x80004003。它看起来像包装做了一些拦截在这里...
我的问题是：是的管理再$ P $的CreateInstance的psentation的声明是否正确？ 我在想什么吗？ （这应该是单纯功能的互操作，应该不是吗？）
其他建议的声明风格也受到欢迎。 感谢名单，马克。
编辑：这个问题似乎出在createInstance方法。我无法获取接口返回由独立同分布的参数要求。
[preserveSig]
[返回：的MarshalAs（UnmanagedType.Error）
INT32的CreateInstance（[IN] REF的Guid的classId，[在] REF的Guid interfaceId，[的MarshalAs（UnmanagedType.IUnknown，IidParameterIndex = 1），输入，输出]参考对象实例）;
我也试图UnmanagedType.Interface结合的IidParameterIndex但都导致一个的IUnknown被封送回。如果我重新查询IPluginBase接口IPluginBase ::初始化方法的工作原理（断点管理code命中）。
编辑：这个问题似乎出在createInstance方法。我是 无法获得接口返回的是受独立同分布问 参数。
指定 IidParameterIndex 没有帮助在这里。你的执行 createInstance建立的应该是这样的：
公众诠释createInstance建立（REF的Guid的classId，裁判的Guid RIID，楼盘的IntPtr实例）
{
如果（比如！= IntPtr.Zero）
返回E_POINTER;
//代替实际的对象创建$ C $下的CreateObject
obj对象=的CreateObject（的classId）
//返回正确的接口
IntPtr的UNK = Marshal.GetIUnknownForObject（OBJ）;
尝试
{
返回Marshal.QueryInterface（UNK，裁判RIID，出实例）;
}
最后
{
Marshal.Release（UNK）;
}
}
This is a follow up from my previous post. Read that post for context. Note that it is not strict COM interop - but the C++ interfaces are COM compatible.
Im trying to implement this C++ interface in C#
class IPluginFactory : public FUnknown
{
virtual tresult PLUGIN_API createInstance (FIDString cid, FIDString iid, void** obj) = 0;
};
My C# code looks like this:
[ComImport]
[Guid(Interfaces.IPluginFactory)]
[InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
public interface IPluginFactory
{
[PreserveSig]
[return: MarshalAs(UnmanagedType.Error)]
Int32 CreateInstance([In] ref Guid classId, [In] ref Guid interfaceId, [MarshalAs(UnmanagedType.IUnknown), In, Out] ref object instance);
}
The implementation assigns a new object instance to the 'instance' parameter and returns 0 (S_OK). I even cast to the expected (managed) interface.
instance = (IPluginBase)new PluginBase();
return 0;
The object returned is represented by this C++ interface:
class IPluginBase: public FUnknown
{
public:
virtual tresult PLUGIN_API initialize (FUnknown* context) = 0;
virtual tresult PLUGIN_API terminate () = 0;
};
Which looks like this in my C# implementation:
[ComImport]
[Guid(Interfaces.IPluginBase)]
[InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
public interface IPluginBase
{
[PreserveSig]
[return: MarshalAs(UnmanagedType.Error)]
Int32 Initialize([MarshalAs(UnmanagedType.IUnknown), In] object context);
[PreserveSig]
[return: MarshalAs(UnmanagedType.Error)]
Int32 Terminate();
}
In the unmanaged C++ test application I wrote, I can successfully call createInstance and receive a non-null pointer the code uses as a IPluginBase*.
The problem comes when I try to call the 'initialize' method on this IPluginBase* pointer. It never reaches the managed code (no breakpoint is hit - other breakpoint work fine) and the return code is 0x80004003. It looks like the wrapper does some intercepting here...
My question is: is the declaration of the managed representation of CreateInstance correct? What am I missing here? (this should be plain vanilla interop, should it not?)
Other suggestions on declaration 'style' are also welcome. Thanx, Marc.
EDIT: The problem seems to lie with the createInstance method. I am unable to get the interface returned that is asked for by the iid parameter.
[PreserveSig]
[return: MarshalAs(UnmanagedType.Error)]
Int32 CreateInstance([In] ref Guid classId, [In] ref Guid interfaceId, [MarshalAs(UnmanagedType.IUnknown, IidParameterIndex = 1), In, Out] ref object instance);
I have also tried UnmanagedType.Interface in combination with the IidParameterIndex but both result in a IUnknown being marshaled back. If I re-query the IPluginBase interface the IPluginBase::initialize method works (breakpoint in managed code hits).
EDIT: The problem seems to lie with the createInstance method. I am unable to get the interface returned that is asked for by the iid parameter.
Specifying IidParameterIndex doesn't help here. Your implementation of createInstance should look like this:
public int createInstance(ref Guid classId, ref Guid riid, ref IntPtr instance)
{
if (instance != IntPtr.Zero)
return E_POINTER;
// substitute your actual object creation code for CreateObject
object obj = CreateObject(classId)
// return the correct interface
IntPtr unk = Marshal.GetIUnknownForObject(obj);
try
{
return Marshal.QueryInterface(unk, ref riid, out instance);
}
finally
{
Marshal.Release(unk);
}
}
这篇关于从C ++中的COM互操作的不叫回来管理对象的方法的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
