Question

我想使用WmiMonitorBrightness：CurrentBrightness的属性来获取亮度值。

在Win10中，使用C＃＆amp; C ++（通过MFC）程序可以获得系统亮度。我在相同的计算机上将操作系统更改为Win7，C＃程序可以获得正确的亮度;但是，C ++程序无法获得正确的值。相反，它显示乱码（没有例外）。

有没有人遇到类似的情况？希望有人能给我一些建议。提前谢谢！

C＃ref：How to query GetMonitorBrightness from C#

我的C ++代码（只需修改https://msdn.microsoft.com/en-us/library/aa390423(v=vs.85).aspx中的第4步，第6步和第7步，以符合我的需要）：

步骤4：

//Connect to WMI through the IWbemLocator::ConnectServer method

IWbemServices *pSvc = NULL;

hres = pLoc->ConnectServer(
    _bstr_t(L"ROOT\\WMI"),   // Object path of WMI namespace
    NULL,                    // User name. NULL = current user
    NULL,                    // User password. NULL = current
    0,                       // Locale. NULL indicates current
    NULL,                    // Security flags.
    0,                       // Authority (for example, Kerberos)
    0,                       // Context object 
    &pSvc                    // pointer to IWbemServices proxy
    );

if (FAILED(hres))
{
    cout << "Could not connect. Error code = 0x"
            << hex << hres << endl;
    pLoc->Release();
    CoUninitialize();
    return 1;                // Program has failed.
}

cout << "Connected to ROOT\\WMI namespace" << endl;

第6步：

// Use the IWbemServices pointer to make requests of WMI

// For example, get the name of the operating system
IEnumWbemClassObject* pEnumerator = NULL;
hres = pSvc->ExecQuery(
    bstr_t("WQL"),
    bstr_t("SELECT * FROM WmiMonitorBrightness"),
    WBEM_FLAG_FORWARD_ONLY | WBEM_FLAG_RETURN_IMMEDIATELY,
    NULL,
    &pEnumerator);

if (FAILED(hres))
{
    cout << "Query for operating system name failed."
        << " Error code = 0x"
        << hex << hres << endl;
    pSvc->Release();
    pLoc->Release();
    CoUninitialize();
    return 1;               // Program has failed.
}

第7步：

// Get the data from the query in step 6

IWbemClassObject *pclsObj = NULL;
ULONG uReturn = 0;

while (pEnumerator)
{
    HRESULT hr = pEnumerator->Next(
        WBEM_INFINITE,  //lTimeOut [in]
        1,              //Number of requested objects.
        &pclsObj,       //Pointer to enough storage to hold the number of IWbemClassObject 
                                //interface pointers specified by uCount. 
        &uReturn        //Pointer to a ULONG that receives the number of objects returned.
                                //This number can be less than the number requested in uCount.
        );

    if (0 == uReturn)
    {
        break;
    }

    VARIANT vtProp;

    // Get the value of the Name property
    hr = pclsObj->Get(L"CurrentBrightness", 0, &vtProp, 0, 0);
    wcout << " CurrentBrightness : " << vtProp.intVal << endl;

    pclsObj->Release();
}

// Cleanup
pSvc->Release();
pLoc->Release();
pEnumerator->Release();
CoUninitialize();

WmiMonitorBrightness不适用于C ++的Win7

0 个答案: