C++托管代码使用句柄调用非托管代码

发布于 2024-10-07 15:03:15 字数 1285 浏览 6 评论 0原文

经过一下午的搜索，这个问题把我难住了！我正在编写一个托管 C++ 应用程序，它需要调用一些非托管代码。这是我需要调用的函数：

public: void Connect(
    [out] LONG* pCookieID, 
    [out] LONG* pNumberOfStreams, 
    [out] VARIANT* pMediaType
);

文档中有这样的说明：参数 pMediaType 必须在 C# 中设置为 null，而在 VB .NET 中则不设置任何内容code> 在调用 Connect 之前，否则将抛出错误代码为 DISP_E_TYPEMISMATCH = 0x80020005 的异常。

所以我需要将 3 个句柄传递给该函数，以便它返回其中的数据。两个 LONG 句柄看起来相当简单，但我不知道如何传递变体的句柄。

这就是我必须要做的：

int ^cookieID;
int ^numberOfStreams;
System::Object ^buffer;

GCHandle hcookieID = GCHandle::Alloc(cookieID, GCHandleType::Pinned);
GCHandle hnumberOfStreams = GCHandle::Alloc(numberOfStreams, 
    GCHandleType::Pinned);
GCHandle hbuffer = GCHandle::Alloc(buffer, GCHandleType::Pinned);

parser->Connect(hcookieID.AddrOfPinnedObject().ToInt32(),
    hnumberOfStreams.AddrOfPinnedObject().ToInt32(),
    (System::Object^)hbuffer.AddrOfPinnedObject().ToInt32());

hcookieID.Free();
hnumberOfStreams.Free();
hbuffer.Free();

编译器接受这一点，但是当调用 Connect 方法时，我收到以下错误：

“类型不匹配。（HRESULT 异常：0x80020005
(DISP_E_TYPEMISMATCH))"} System::Exception^

我到处搜索并尝试了各种解决方案，但找不到任何解决方案。

原文

After an afternoon of searching this problem has got me stumped! I'm writing a managed C++ application which needs to call some unmanaged code. This is the function I need to call:

public: void Connect(
    [out] LONG* pCookieID, 
    [out] LONG* pNumberOfStreams, 
    [out] VARIANT* pMediaType
);

And the documentation has this note: Parameter pMediaType must be set to null in C# and nothing in VB .NET before calling Connect, otherwise an exception with error code DISP_E_TYPEMISMATCH = 0x80020005 will be thrown.

So I need to pass 3 handles to the function for it to return data in them. The two LONG handles seem reasonably straightforward but I can't figure out how to pass a handle for a variant.

This is where I've got to:

int ^cookieID;
int ^numberOfStreams;
System::Object ^buffer;

GCHandle hcookieID = GCHandle::Alloc(cookieID, GCHandleType::Pinned);
GCHandle hnumberOfStreams = GCHandle::Alloc(numberOfStreams, 
    GCHandleType::Pinned);
GCHandle hbuffer = GCHandle::Alloc(buffer, GCHandleType::Pinned);

parser->Connect(hcookieID.AddrOfPinnedObject().ToInt32(),
    hnumberOfStreams.AddrOfPinnedObject().ToInt32(),
    (System::Object^)hbuffer.AddrOfPinnedObject().ToInt32());

hcookieID.Free();
hnumberOfStreams.Free();
hbuffer.Free();

The compiler accepts this but when the Connect method is called I get the following error: