Question

我正在使用COM库“Microsoft Scripting Runtime”（c：\ windows \ System32 \ scrrun.dll）中的Scripting.Dictionary。我正在使用import来获取我的包装器，这些都有效。添加一些项目后，我正在尝试获取密钥列表，但我被卡住了。

我有办法。我可以从词典中获取SAFEARRAY个键，但我想使用CComSafeArray中定义的<atlsafe.h>类，但我无法找到一个好的构造。目前，构造函数抛出ATL断言抱怨vartype不匹配。不可否认，新构建的CComSafeArray的CCCC为vartype为52428（十六进制），看起来可能与未初始化的内存相似。但推断的类型看起来也不正确，我期望safearray的vartype是字符串，但断言代码给出了vartype 12，即UI2。很奇怪。

无论如何，对于熟悉这一点的人来说，这可能很容易。这是一个控制台程序Minimal，Complete，Verifiable，Example（MCVE），符合SO标准。

#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));

对此：

SAFEARRAY* keys = varColoursKeys.parray;

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

然后，您可以向keys查询其vt：

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

请注意，varColours = keys将生成数组数据的副本。如果这不是您真正想要的，那么您应该Detach()来自CComVariant的数组（或直接使用VARIANT而不是CComVariant）和Attach()它到CComSafeArray（然后你可以使用CComSafeArray::GetType()方法）。

此外，在调用CoUninitialize() 之前，您需要确保所有COM包装都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键方法返回SAFEARRAY的CComSafeArray

1 个答案: