@Robins.Lee The ExecMethod alway return WBEM_E_INVALID_METHOD_PARAMETERS because you pass the class name for the first parameter, but it needs a valid the object path of the object for which the method is executed.
You only obtained this class, not the object of this class. You can use "SELECT * FROM WmiMonitorDescriptorMethods" to get the pEnumerator of the class object, then get the path of each object, and then call WmiGetMonitorRawEEdidV1Block for each object.

    IEnumWbemClassObject* pEnumerator = NULL;  
    wstring strQuery = L"SELECT * FROM WmiMonitorDescriptorMethods";  
    hres = pSvc->ExecQuery(BSTR(L"WQL"), BSTR(strQuery.c_str()),  
        WBEM_FLAG_FORWARD_ONLY | WBEM_FLAG_RETURN_IMMEDIATELY, NULL, &pEnumerator);  
      
    ULONG uReturn = 0;  
    while (pEnumerator)  
    {  
        IWbemClassObject* pclsObj = NULL;  
        UINT32 bit = 0;  
        hres = pEnumerator->Next(WBEM_INFINITE, 1, &pclsObj, &uReturn);  
  
        if (0 == uReturn || FAILED(hres))  
            break;  
        VARIANT var;  
        pclsObj->Get(L"__PATH", 0, &var, NULL, NULL);  
        ...  
        hres = pSvc->ExecMethod(var.bstrVal, MethodName, 0, NULL, pClassInstance, &pOutParams, NULL);  
        ...  
    }  

The following sample works for me:

#define _WIN32_DCOM  
  
#include <iostream>  
using namespace std;  
  
#include <comdef.h>  
#include <Wbemidl.h>  
  
#pragma comment(lib, "wbemuuid.lib")  
int main(int iArgCnt, char** argv)  
{  
    HRESULT hres;  
    // Step 1: --------------------------------------------------  
 // Initialize COM. ------------------------------------------  
    hres = CoInitializeEx(0, COINIT_MULTITHREADED);  
    if (FAILED(hres))  
    {  
        cout << "Failed to initialize COM library. Error code = 0x"  
            << hex << hres << endl;  
        return 1;                  // Program has failed.  
    }  
    // Step 2: --------------------------------------------------  
    // Set general COM security levels --------------------------  
    hres = CoInitializeSecurity(  
        NULL,  
        -1,                          // COM negotiates service  
        NULL,                        // Authentication services  
        NULL,                        // Reserved  
        RPC_C_AUTHN_LEVEL_DEFAULT,   // Default authentication   
        RPC_C_IMP_LEVEL_IMPERSONATE, // Default Impersonation  
        NULL,                        // Authentication info  
        EOAC_NONE,                   // Additional capabilities   
        NULL                         // Reserved  
    );  
    //hr = CoInitializeSecurity(  
    //    NULL,   
    //    -1,   
    //    NULL,  
    //    NULL,  
    //    RPC_C_AUTHN_LEVEL_DEFAULT,  
    //    RPC_C_IMP_LEVEL_IMPERSONATE,  
    //    NULL,  
    //    EOAC_NONE,  
    //    NULL);  
    if (FAILED(hres))  
    {  
        cout << "Failed to initialize security. Error code = 0x"  
            << hex << hres << endl;  
        CoUninitialize();  
        return 1;                      // Program has failed.  
    }  
    // Step 3: ---------------------------------------------------  
    // Obtain the initial locator to WMI -------------------------  
    IWbemLocator* pLoc = NULL;  
    hres = CoCreateInstance(  
        CLSID_WbemLocator,  
        0,  
        CLSCTX_INPROC_SERVER,  
        IID_IWbemLocator, (LPVOID*)&pLoc);  
    // CoCreateInstance(  
    //  CLSID_WbemLocator,  
    //  0,  
    //  CLSCTX_INPROC_SERVER,  
    //  IID_IWbemLocator, (LPVOID *) &m_pWmiLoc);  
    if (FAILED(hres))  
    {  
        cout << "Failed to create IWbemLocator object. "  
            << "Err code = 0x"  
            << hex << hres << endl;  
        CoUninitialize();  
        return 1;                 // Program has failed.  
    }  
    // Step 4: ---------------------------------------------------  
    // Connect to WMI through the IWbemLocator::ConnectServer method  
    IWbemServices* pSvc = NULL;  
    // Connect to the local root\cimv2 namespace  
    // and obtain pointer pSvc to make IWbemServices calls.  
    hres = pLoc->ConnectServer(  
        //_bstr_t(L"ROOT\\CIMV2"),  
        _bstr_t(L"ROOT\\WMI"),  
        NULL,  
        NULL,  
        0,  
        NULL,  
        0,  
        0,  
        &pSvc  
    );  
    //hres = m_pWmiLoc->ConnectServer(  
    //     bstrNamespace,  
    //     NULL,  
    //     NULL,  
    //     0,  
    //     NULL,  
    //     0,  
    //     0,  
    //     &m_pWmiServ);  
    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\\CIMV2 WMI namespace" << endl;  
    cout << "Connected to ROOT\\WMI WMI namespace" << endl;  
    // Step 5: --------------------------------------------------  
    // Set security levels for the proxy ------------------------  
    hres = CoSetProxyBlanket(  
        pSvc,                        // Indicates the proxy to set  
        RPC_C_AUTHN_WINNT,           // RPC_C_AUTHN_xxx   
        RPC_C_AUTHZ_NONE,            // RPC_C_AUTHZ_xxx   
        NULL,                        // Server principal name   
        RPC_C_AUTHN_LEVEL_CALL,      // RPC_C_AUTHN_LEVEL_xxx   
        RPC_C_IMP_LEVEL_IMPERSONATE, // RPC_C_IMP_LEVEL_xxx  
        NULL,                        // client identity  
        EOAC_NONE                    // proxy capabilities   
    );  
    //hres = CoSetProxyBlanket(  
    //    m_pWmiServ,   
    //    RPC_C_AUTHN_WINNT,  
    //    RPC_C_AUTHZ_NONE,  
    //    NULL,  
    //    RPC_C_AUTHN_LEVEL_CALL,  
    //    RPC_C_IMP_LEVEL_IMPERSONATE,  
    //    NULL,  
    //    EOAC_NONE);  
    if (FAILED(hres))  
    {  
        cout << "Could not set proxy blanket. Error code = 0x"  
            << hex << hres << endl;  
        pSvc->Release();  
        pLoc->Release();  
        CoUninitialize();  
        return 1;               // Program has failed.  
    }  
    // Step 6: --------------------------------------------------  
    printf("Step 6\n");  
    // Use the IWbemServices pointer to make requests of WMI ----  
    // set up to call the Win32_Process::Create method  
    //BSTR MethodName = SysAllocString(L"Create");  
    //BSTR ClassName = SysAllocString(L"Win32_Process");   
    BSTR MethodName = SysAllocString(L"WmiGetMonitorRawEEdidV1Block");  
    BSTR ClassName = SysAllocString(L"WmiMonitorDescriptorMethods");  
      
#if 0  
    //-------need Add------------------------------------------------  
    DWORD nReturned;  
    IEnumWbemClassObject* m_ppiWmiEnum = NULL;  
    /*  
    HRESULT    CAccessWmi::EnumInstances(CString& csInstName, OUT IEnumWbemClassObject** ppiWmiEnum)  
    {  
    if (NULL == ppiWmiEnum)  
    return E_INVALIDARG;  
    BSTR    bstrObjectName = SysAllocString(csInstName.GetBuffer());  
    HRESULT hr =  m_pWmiServ->CreateInstanceEnum(    bstrObjectName,  
    WBEM_FLAG_RETURN_IMMEDIATELY | WBEM_FLAG_FORWARD_ONLY,  
    NULL,  
    ppiWmiEnum);  
    if (bstrObjectName)  
    SysFreeString(bstrObjectName);  
    return hr;  
    }  
    */  
    hres = pSvc->CreateInstanceEnum(ClassName,  
        WBEM_FLAG_RETURN_IMMEDIATELY | WBEM_FLAG_FORWARD_ONLY,  
        NULL,  
        &m_ppiWmiEnum);  
    if (FAILED(hres))  
    {  
        pSvc->Release();  
        pLoc->Release();  
        CoUninitialize();  
        printf("CreateInstanceEnum err\n");  
    }  
    else  
    {  
        printf("CreateInstanceEnum OK\n");  
    }  
    hres = m_ppiWmiEnum->Next(WBEM_INFINITE, 1, &pClass, &nReturned);  
    if (hres != WBEM_S_NO_ERROR)  
    {  
        printf("m_ppiWmiEnum->Next err\n");  
    }  
    else  
    {  
        printf("m_ppiWmiEnum->Next ok\n");  
    }  
    //--------------------------------------------------------------  
  
#endif  
    IEnumWbemClassObject* pEnumerator = NULL;  
    wstring strQuery = L"SELECT * FROM WmiMonitorDescriptorMethods";  
    hres = pSvc->ExecQuery(BSTR(L"WQL"), BSTR(strQuery.c_str()),  
        WBEM_FLAG_FORWARD_ONLY | WBEM_FLAG_RETURN_IMMEDIATELY, NULL, &pEnumerator);  
      
    ULONG uReturn = 0;  
    while (pEnumerator)  
    {  
        IWbemClassObject* pclsObj = NULL;  
        UINT32 bit = 0;  
        hres = pEnumerator->Next(WBEM_INFINITE, 1, &pclsObj, &uReturn);  
  
        if (0 == uReturn || FAILED(hres))  
            break;  
  
        IWbemClassObject* pClass = NULL;  
        hres = pSvc->GetObject(ClassName, 0, NULL, &pClass, NULL);  
        IWbemClassObject* pInParamsDefinition = NULL;  
        hres = pClass->GetMethod(MethodName, 0, &pInParamsDefinition, NULL);  
        IWbemClassObject* pClassInstance = NULL;  
        hres = pInParamsDefinition->SpawnInstance(0, &pClassInstance);  
  
  
        VARIANT var;  
        pclsObj->Get(L"__PATH", 0, &var, NULL, NULL);  
  
        VARIANT varCommand = { 0 };  
        //varCommand.vt = VT_BSTR;  
        //varCommand.bstrVal = _bstr_t(L"notepad.exe");  
        varCommand.vt = VT_UI1;  
        varCommand.bVal = 0;  
        // Store the value for the in parameters  
        //hres = pClassInstance->Put(L"CommandLine", 0, &varCommand, 0);  
        //wprintf(L"The command is: %s\n", V_BSTR(&varCommand));  
        hres = pClassInstance->Put(L"BlockId", 0, &varCommand, 0);  
        wprintf(L"The BlockId is: %d\n", V_UI1(&varCommand));  
        // Execute Method  
        IWbemClassObject* pOutParams = NULL;  
        hres = pSvc->ExecMethod(var.bstrVal, MethodName, 0,  
            NULL, pClassInstance, &pOutParams, NULL);  
        if (FAILED(hres))  
        {  
            cout << "Could not execute method. Error code = 0x"  
                << hex << hres << endl;  
            VariantClear(&varCommand);  
            SysFreeString(ClassName);  
            SysFreeString(MethodName);  
            pClass->Release();  
            pClassInstance->Release();  
            pInParamsDefinition->Release();  
            pOutParams->Release();  
            pSvc->Release();  
            pLoc->Release();  
            CoUninitialize();  
            return 1;               // Program has failed.  
        }  
  
        VARIANT varReturnValue;  
        //hres = pOutParams->Get(_bstr_t(L"ReturnValue"), 0, &varReturnValue, NULL, 0);  
        hres = pOutParams->Get(_bstr_t(L"BlockType"), 0, &varReturnValue, NULL, 0);  
        if (FAILED(hres))  
        {  
            printf("BlockType err\n");  
        }  
        else  
        {  
            printf("BlockType:%d\n", varReturnValue.bVal);  
        }  
        // Clean up  
        //--------------------------  
        VariantClear(&var);  
        VariantClear(&varCommand);  
        VariantClear(&varReturnValue);  
        pClass->Release();  
        pClassInstance->Release();  
        pInParamsDefinition->Release();  
        pOutParams->Release();  
        pclsObj->Release();  
    }  
    if (FAILED(hres))  
    {  
        printf("pClass->GetMethod err\n");  
    }  
    else  
    {  
        printf("pClass->GetMethod ok\n");  
    }  
    //--------------------------  
    SysFreeString(ClassName);  
    SysFreeString(MethodName);  
  
    pLoc->Release();  
    pSvc->Release();  
    pEnumerator->Release();  
    CoUninitialize();  
    return 0;  
}  

If the answer is helpful, please click "Accept Answer" and upvote it.

Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.