COM SAFEARRAY的GUID从C ++返回到C＃ [英] COM SAFEARRAY of GUID's returned from C++ to C#

问题描述

目前，我正在运行到需要传递一个SAFEARRAY（GUID）从C ++到C＃一个返回值的问题。

I'm currently running into an issue of needing to pass a SAFEARRAY(GUID) as a return value from C++ to C#.

目前的C＃侧使用。一个互操作的dll从Tlbimp.exe将（类型库导入）生成的

Currently the C# side is using an Interop dll generated from Tlbimp.exe (Type Library Importer).

IDL是：

HRESULT GetGuids(
    [out]SAFEARRAY(GUID)* guids);

我也试过[出来，RETVAL]

I've also tried [out, retval]

函数签名是：

HRESULT
WINAPI
MyClass::GetGuids(SAFEARRAY** guids)

如果我用 SafeArrayCreate（）或 SafeArrayCreateVector（）：

SAFEARRAY* psa
psa = SafeArrayCreate(VT_CLSID, 1, rgsabound);

我得到一个空 SAFEARRAY 指针，该指针应该说明 E_OUTOFMEMORY 这是不正确。

I get a NULL SAFEARRAY pointer, which is supposed to indicate E_OUTOFMEMORY which is incorrect.

我发现那是什么 VT_CLSID 仅供奥莱属性集，而不是SAFEARRAY的：
的 http://poi.apache.org/apidocs/org/apache/poi/hpsf/Variant.html 它表明CLSID为

What I did find was that VT_CLSID is only for Ole property sets and not SAFEARRAY's: http://poi.apache.org/apidocs/org/apache/poi/hpsf/Variant.html Its indicated that CLSID is

我也尝试构建安全阵列的替代方法：
SafeArrayAllocDescriptor（）和 SafeArrayAllocData（）

I've also tried the alternate means of constructing the safe array with: SafeArrayAllocDescriptor() and SafeArrayAllocData().

hResult = SafeArrayAllocDescriptor(1, guids)
hResult = SafeArrayAllocData(*guids);

这让我创建磁盘阵列，但 SafeArrayPutElement填充时，（） 我得到的一个80070057 HRESULT（参数不正确）。这可能是由于它采用 VT_CLSID 参数以及事实

This lets me create the array, but when populating it with SafeArrayPutElement() I get an HRESULT of 0x80070057 (The parameter is incorrect). This is probably due to the fact it takes the VT_CLSID parameter as well

我可以手动<$填充C $ C> SafeArrayAccessData（）

GUID* pData = NULL;
hResult = SafeArrayAccessData(*guids, (void**)&pData);

但我从C＃端的错误：
的值，不在范围内在预期的范围

but I get an error from the C# side: "The value does not fall within the expected Range"

我不知道如何完成或者由retval的或out参数返回SAFEARRAY（GUID）到C＃中所需的功能。

I'm not sure how to accomplish the desired functionality of returning a SAFEARRAY(GUID) to C# either by a retval or out parameter.

这似乎应该是简单的 - 有在IDL许多领域我已经通过GUID的没有任何UDT的或编组。直到我需要把它们放入一个SAFEARRAY一切工作正常。

It seems it should be simple - there are many areas in the IDL where I'm already passing GUID's without any UDT's or marshalling. Everything works fine until I need to pass them in a SAFEARRAY.

任何帮助表示赞赏，提前
谢谢

Any help is appreciated, Thanks in advance

推荐答案

您是绝对正确的 - 问题是，VT_CLSID没有在任何VARIANT或SAFEARRAY允许的。它归结为GUID不是自动化兼容的类型。

You're absolutely right - the problem is that VT_CLSID isn't allowed in either VARIANT or SAFEARRAY. It boils down to GUID not being an Automation-compatible type.

我经常需要做的，你想同样的事情。解决此问题的最简单的方法是将GUID转换为字符串，然后传递SAFEARRAY（VT_BSTR）。它违背了粮食某种程度上做这种转换，但我想你可以把认为有编组的反正怎么回事，这种转换是一种封送的。

I often need to do the same thing that you're trying. The easiest way around the problem is to convert the GUID to a string and then pass SAFEARRAY(VT_BSTR). It goes against the grain somewhat to do this conversion, but I suppose you could take the view that there's marshaling going on anyway and this conversion is a type of marshaling.

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