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,这些包装器正在工作。添加一些项目后,我试图获取键列表,但我卡住了。
我有办法。我可以得到 SAFEARRAY
字典中的键,但我想使用 CComSafeArray
<atlsafe.h>
中定义的类但我无法找出一个好的结构。目前,构造函数抛出 ATL
断言提示 vartype
不匹配。不可否认,新构造的 CComSafeArray 有一个 vartype
十六进制 CCCC 的 52428,这看起来可能像是未初始化的内存。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 vartype 12,即 UI2。很奇怪。
无论如何,这对于熟悉这一点的人来说可能很容易。这是一个符合 SO 标准的控制台程序“最小、完整、可验证、示例”(MCVE)。
#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;
}
最佳答案
更改此:
SAFEARRAY keys(*(varColoursKeys.parray));
对此:
SAFEARRAY* keys = varColoursKeys.parray;
(可选,首先确保 varColoursKeys.vt
具有 VT_ARRAY
标志)
然后你可以查询keys
的vt
:
hr = ::ATL::AtlSafeArrayGetActualVartype(keys, &vt);
请注意,varColours = keys
将创建数组数据的拷贝。如果这不是您真正想要的,那么您应该从 CComVariant
中 Detach()
数组(或者直接使用 VARIANT
而不是CComVariant
)并将其 Attach()
附加到 CComSafeArray
(然后您可以使用 CComSafeArray::GetType()
方法)。
此外,在调用 CoUninitialize()
之前,您需要确保所有 COM 包装器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;
}
关于c++ - 如何初始化 SAFEARRAY 从 Scripting.Dictionary Keys 方法返回的 CComSafeArray,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/49619401/