c++ - (WMI) ExecMethod 输出参数 - 无论调用结果如何，ResultingSnapshot 都是 NULL，为什么？

Question

我正在使用 WMI 创建 RCT 检查点。下面是代码片段。问题是当我使用 ExecMethod 调用方法 Create Snapshot 时，检查点被创建但 ResultingSnapshot 仍然指向 NULL.

由于调用是异步的(因为 pOutParameters 的返回值是 4096)我也在 WaitForJobCompletion 中等待作业完成，但是 pOutParameters 未更新，ResultingSnapshot 仍为 NULL。

基本上，我需要这个 ResultingSnapshot 来创建引用点。如果有任何其他方法可以做到这一点，我可以写出来，但需要指导。

我是 WMI 的新手，感谢任何帮助或领导。

HRESULT hr;
CComPtr<IWbemClassObject> pInParams;
CComPtr<IWbemClassObject> pOutParameters;
IWbemCallResult *pResult = 0;

// Set Method Paramters
this->GetMethodParams(L"Msvm_VirtualSystemSnapshotService", L"CreateSnapshot", &pInParams);

IWbemClassObject * pVirtualSystemSnaphotSettingData = NULL;
hr = m_pWbemServices->GetObject(L"Msvm_VirtualSystemSnapshotSettingData", 0, NULL, &pVirtualSystemSnaphotSettingData, &pResult);

IWbemClassObject * pInpInstOfSnapshotSettingData = NULL;
hr = pVirtualSystemSnaphotSettingData->SpawnInstance(0, &pInpInstOfSnapshotSettingData);

VARIANT consistencyLevel;
VariantInit(&consistencyLevel);
V_VT(&consistencyLevel) = VT_BSTR;
V_BSTR(&consistencyLevel) = SysAllocString(L"1");
hr = pInpInstOfSnapshotSettingData->Put(L"ConsistencyLevel", 0, &consistencyLevel, 0);
VariantClear(&consistencyLevel);

VARIANT elementName;
VariantInit(&elementName);
V_VT(&elementName) = VT_BSTR;
V_BSTR(&elementName) = SysAllocString(L"rhel-1");
hr = pInpInstOfSnapshotSettingData->Put(L"ElementName", 0, &elementName, 0);
VariantClear(&elementName);

hr = m_pWbemServices->PutInstance(pInpInstOfSnapshotSettingData, 0, NULL, &pResult);

BSTR objString = NULL;
hr = pInpInstOfSnapshotSettingData->GetObjectText(0, &objString);
BSTR ArgNameTwo = SysAllocString(L"SnapshotSettings");
VARIANT v;
V_VT(&v) = VT_BSTR;
V_BSTR(&v) = objString; 

hr = pInParams->Put(ArgNameTwo, 0, &v, 0);

VARIANT vtProp;
m_pVmWbemClassObject->Get(L"__Path", 0, &vtProp, 0, 0);

wprintf(L"Affected System : : %ls", (LPWSTR)vtProp.bstrVal);
HRESULT hres = pInParams->Put(L"AffectedSystem", 0 , &vtProp, NULL);

VARIANT var;
VariantInit(&var);
V_VT(&var) = VT_BSTR;
V_BSTR(&var) = SysAllocString(L"2");


CHK_HRES(pInParams->Put(L"SnapshotType", 0, &var, 0));


IEnumWbemClassObject* pEnumOb = NULL;
hr = m_pWbemServices->ExecQuery(
BSTR(L"WQL"),
BSTR(L"select * from Msvm_VirtualSystemSnapshotService"),
WBEM_FLAG_FORWARD_ONLY | WBEM_FLAG_RETURN_IMMEDIATELY,
NULL,
&pEnumOb);
IWbemClassObject *pclsObj1 = NULL;
ULONG uReturn1 = 0;

while (1)
{
    HRESULT hr = pEnumOb->Next(WBEM_INFINITE, 1, &pclsObj1, &uReturn1);

    if (0 == uReturn1)
    {
        break;
    }

    IWbemCallResult *pCallResult = NULL;
    IWbemClassObject *pResObj = NULL;

    CComBSTR path(this->GetStrProperty(L"__PATH", pclsObj1));

    hr = m_pWbemServices->ExecMethod(path, L"CreateSnapshot", 0, NULL, pInParams, &pOutParameters, &pCallResult);



    /* cout << "check1 : " << hex << hr << endl;
    hr = pCallResult->GetResultObject(0, &pResObj);
    cout << "check2" << endl;*/

    this->WaitForJobCompletion(pOutParameters);
   }

cout << "\nSnpshot Complete" << endl;
}

编辑 我发现 SnapshotType 参数设置不正确，它应该是 32768，我使用以下方法将 uint16 转换为 Variant 但没有成功，我得到了 0x80070057 Incorrect Parameter 错误。

VARIANT var;
VariantInit(&var);
V_VT(&var) = VT_BSTR;
V_BSTR(&var) = SysAllocString(L"32768");

hr = pInParams->Put(L"SnapshotType", 0, &var, CIM_UINT16);

Answer 1

HRESULT GetRelated(PWSTR sAssociatePath, PWSTR sResultClass, IWbemClassObject** ppResultObject)
{
CStringW query;
query.Format(L"associators of {%s} where ResultClass = %s", sAssociatePath, sResultClass);

CComPtr<IEnumWbemClassObject> pEnumOb;

HRESULT hr = m_pWbemServices->ExecQuery(
    BSTR(L"WQL"),
    CComBSTR(query),
    WBEM_FLAG_FORWARD_ONLY | WBEM_FLAG_RETURN_IMMEDIATELY,
    NULL,
    &pEnumOb));
ULONG uReturn = 0;
CComPtr<IWbemClassObject> pObject;
hr = pEnumOb->Next(WBEM_INFINITE, 1, &pObject, &uReturn);
return hr;
}
// Call the GetRelated function above with the __PATH parameter of JOB
CComPtr<IWbemClassObject> pOutParam = NULL;
CHK_HRES(this->ExecMethod(pHyperVObject, L"ConvertToReferencePoint", pInParams, &pOutParam, NULL));
CComVariant jobPath;
CHK_HRES(pOutParam->Get(L"Job", 0, &jobPath, NULL, NULL));
CComPtr<IWbemClassObject> pResult;
GetRelated(jobPath.bstrVal, L"Msvm_VirtualSystemReferencePoint", &pResult);