如何初始化从 Scripting.Dictionary Keys 方法返回的 SAFEARRAY CComSafeArray

Question

我正在使用来自 COM 库 "Microsoft Scripting Runtime" (c:\windows\System32\scrrun.dll) 的 Scripting.Dictionary。我正在使用 import 来获取我的包装器，它们正在工作。添加一些项目后，我试图获取键列表，但我卡住了。

我有办法了。我可以从字典中获取 SAFEARRAY 键，但我想使用 <atlsafe.h> 中定义的 CComSafeArray class，但我想不出一个好的结构。目前，构造函数抛出一个 ATL 断言抱怨 vartype 不匹配。诚然，新构造的 CComSafeArray 有一个 vartype 的十六进制 CCCC 52428，这看起来可能像未初始化的内存。但是推断的类型看起来也不正确，我希望 safearray 的 vartype 是字符串，但断言代码给出 vartype 12，即 UI2。很奇怪。

无论如何，对于熟悉此内容的人来说，这可能很容易。这是一个符合 SO 标准的最小、完整、可验证、示例 (MCVE) 控制台程序。

#include "stdafx.h"
#include <atlbase.h>
#include <atlsafe.h>

#import "c:\windows\System32\scrrun.dll" raw_interfaces_only,raw_native_types, named_guids, rename("DeleteFile", "_DeleteFile"), rename("MoveFile","_MoveFile"), rename("CopyFile", "_CopyFile"), rename("GetFreeSpace", "_GetFreeSpace")

int main()
{
    HRESULT hr = S_OK;

    CoInitialize(0);

    CComQIPtr<Scripting::IDictionary> dictColours;
    hr = dictColours.CoCreateInstance(__uuidof(Scripting::Dictionary));
    if (!SUCCEEDED(hr)) { return hr; }

    CComVariant varZero(0); //dummy value, only interested in keys

    hr = dictColours->Add(&variant_t(L"red"), &varZero);
    if (!SUCCEEDED(hr)) { return hr; }

    hr = dictColours->Add(&variant_t(L"green"), &varZero);
    if (!SUCCEEDED(hr)) { return hr; }

    hr = dictColours->Add(&variant_t(L"blue"), &varZero);
    if (!SUCCEEDED(hr)) { return hr; }

    long lColourCount(0);
    hr = dictColours->get_Count(&lColourCount);
    if (!SUCCEEDED(hr)) { return hr; }

    CComVariant varColoursKeys;
    hr = dictColours->Keys(&varColoursKeys);
    if (!SUCCEEDED(hr)) { return hr; }

    SAFEARRAY keys(*(varColoursKeys.parray));

    //fine up to this point

    CComSafeArray<VARIANT> varColours;

    /* The following code throws an error for the next (line) live, vt=52428 or hex CCCC which looks like uninitialised memory
       whilst GetType() returns 12 which is UI2 (and somehow I expected string type 8!) 
    VARTYPE vt;
    HRESULT hRes = ::ATL::AtlSafeArrayGetActualVartype(const_cast<LPSAFEARRAY>(psaSrc), &vt);
    ATLENSURE_SUCCEEDED(hRes);
    ATLENSURE_THROW(vt == GetType(), E_INVALIDARG);
    */

    varColours = (keys);

    CoUninitialize();
    return 0;
}

Answer 1

改变这个：

SAFEARRAY keys(*(varColoursKeys.parray));

为此：

SAFEARRAY* keys = varColoursKeys.parray;

（可选，首先确保 varColoursKeys.vt 具有 VT_ARRAY 标志）

然后你可以查询 keys 它的 vt:

hr = ::ATL::AtlSafeArrayGetActualVartype(keys, &vt);

请注意，varColours = keys 将对数组数据进行复制。如果这不是您真正想要的，那么您应该 Detach() 来自 CComVariant 的数组（或者直接使用 VARIANT 而不是 CComVariant）和 Attach()它到CComSafeArray（然后你可以使用CComSafeArray::GetType()方法）。

另外，在调用 CoUninitialize().

之前，您需要确保所有 COM 包装器超出范围并释放资源
试试这个：

#include "stdafx.h" #include <atlbase.h> #include <atlsafe.h> #import "c:\windows\System32\scrrun.dll" raw_interfaces_only,raw_native_types, named_guids, rename("DeleteFile", "_DeleteFile"), rename("MoveFile","_MoveFile"), rename("CopyFile", "_CopyFile"), rename("GetFreeSpace", "_GetFreeSpace") HRESULT DoIt() { CComQIPtr<Scripting::IDictionary> dictColours; hr = dictColours.CoCreateInstance(__uuidof(Scripting::Dictionary)); if (FAILED(hr)) { return hr; } CComVariant varZero(0); //dummy value, only interested in keys hr = dictColours->Add(&variant_t(L"red"), &varZero); if (FAILED(hr)) { return hr; } hr = dictColours->Add(&variant_t(L"green"), &varZero); if (FAILED(hr)) { return hr; } hr = dictColours->Add(&variant_t(L"blue"), &varZero); if (FAILED(hr)) { return hr; } long lColourCount(0); hr = dictColours->get_Count(&lColourCount); if (FAILED(hr)) { return hr; } VARIANT varColoursKeys; hr = dictColours->Keys(&varColoursKeys); if (FAILED(hr)) { return hr; } CComSafeArray<VARIANT> varColours; varColours.Attach(varColoursKeys.parray); // use varColours as needed... VARTYPE vt = varColours.GetType(); LONG lLower = varColours.GetLowerBound(); LONG lUpper = varColours.GetUpperBound(); for (LONG i = lLower; i <= lUpper; ++i) { VARIANT &v = varColours.GetAt(i); // use v.bstrVal as needed ... } //... return S_OK; } int main() { HRESULT hr = CoInitialize(0); if (FAILED(hr)) { return hr; } hr = DoIt(); CoUninitialize(); return hr; }

如何初始化从 Scripting.Dictionary Keys 方法返回的 SAFEARRAY CComSafeArray

How to initialise CComSafeArray which a SAFEARRAY returned from a Scripting.Dictionary Keys method

c++

safearray

scripting.dictionary