範例：建立 WMI 應用程式

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06/13/2023

您可以使用本主題中的程式和程式碼範例來建立完整的 WMI 用戶端應用程式，以執行 COM 初始化、連線到本機電腦上的 WMI、讀取一些資料，以及清除。連線到遠端電腦上的 WMI 描述如何從遠端電腦取得資料。

下列套裝程式含所有 C++ WMI 應用程式所需的所有步驟。

使用 對 CoInitializeEx的呼叫，初始化 COM 參數。

如需詳細資訊，請參閱初始化 WMI 應用程式的 COM。
藉由呼叫 CoInitializeSecurity，初始化 COM 進程安全性。

如需詳細資訊，請參閱使用 C++ 設定預設進程安全性層級。
藉由呼叫IWbemLocator：：ConnectServer，取得指定主機電腦上命名空間的IWbemServices指標，也就是簡單案例中的本機電腦。

若要連線到遠端電腦，例如Computer_A，請使用下列物件路徑參數：
```
_bstr_t(L"\\COMPUTER_A\ROOT\\CIMV2")
```
如需詳細資訊，請參閱建立與 WMI 命名空間的連線。
設定 IWbemServices Proxy 安全性，讓 WMI 服務可以藉由呼叫 CoSetProxyBlanket來模擬用戶端。

如需詳細資訊，請參閱在 WMI 連線上設定安全性層級。
使用 IWbemServices 指標來提出 WMI 的要求。例如，查詢所有 Win32_Service 實例，以判斷哪些服務已停止。

如需詳細資訊，請參閱操作類別和實例資訊、查詢 WMI和接收 WMI 事件。
清除物件和 COM。

如需詳細資訊，請參閱清除和關閉 WMI 應用程式。

下列範例程式碼是完整的 WMI 用戶端應用程式。


#define _WIN32_DCOM
#include <iostream>
using namespace std;
#include <comdef.h>
#include <Wbemidl.h>

#pragma comment(lib, "wbemuuid.lib")

int main(int argc, char **argv)
{
    HRESULT hres;

    // 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.
    }

    // Initialize 
    hres =  CoInitializeSecurity(
        NULL,     
        -1,      // COM negotiates service                  
        NULL,    // Authentication services
        NULL,    // Reserved
        RPC_C_AUTHN_LEVEL_DEFAULT,    // authentication
        RPC_C_IMP_LEVEL_IMPERSONATE,  // Impersonation
        NULL,             // Authentication info 
        EOAC_NONE,        // Additional capabilities
        NULL              // Reserved
        );

                      
    if (FAILED(hres))
    {
        cout << "Failed to initialize security. " 
            << "Error code = 0x" 
            << hex << hres << endl;
        CoUninitialize();
        return 1;          // Program has failed.
    }

    // Obtain the initial locator to Windows Management
    // on a particular host computer.
    IWbemLocator *pLoc = 0;

    hres = CoCreateInstance(
        CLSID_WbemLocator,             
        0, 
        CLSCTX_INPROC_SERVER, 
        IID_IWbemLocator, (LPVOID *) &pLoc);
 
    if (FAILED(hres))
    {
        cout << "Failed to create IWbemLocator object. "
            << "Error code = 0x"
            << hex << hres << endl;
        CoUninitialize();
        return 1;       // Program has failed.
    }

    IWbemServices *pSvc = 0;

    // Connect to the root\cimv2 namespace with the
    // current user and obtain pointer pSvc
    // to make IWbemServices calls.

    hres = pLoc->ConnectServer(
        
        _bstr_t(L"ROOT\\CIMV2"), // WMI namespace
        NULL,                    // User name
        NULL,                    // User password
        0,                       // Locale
        NULL,                    // Security flags                 
        0,                       // Authority       
        0,                       // Context object
        &pSvc                    // 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\\CIMV2 WMI namespace" << endl;

    // Set the IWbemServices proxy so that impersonation
    // of the user (client) occurs.
    hres = CoSetProxyBlanket(
       
       pSvc,                         // the proxy to set
       RPC_C_AUTHN_WINNT,            // authentication service
       RPC_C_AUTHZ_NONE,             // authorization service
       NULL,                         // Server principal name
       RPC_C_AUTHN_LEVEL_CALL,       // authentication level
       RPC_C_IMP_LEVEL_IMPERSONATE,  // impersonation level
       NULL,                         // client identity 
       EOAC_NONE                     // proxy capabilities     
    );

    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.
    }


    // Use the IWbemServices pointer to make requests of WMI. 
    // Make requests here:

    // For example, query for all the running processes
    IEnumWbemClassObject* pEnumerator = NULL;
    hres = pSvc->ExecQuery(
        bstr_t("WQL"), 
        bstr_t("SELECT * FROM Win32_Process"),
        WBEM_FLAG_FORWARD_ONLY | WBEM_FLAG_RETURN_IMMEDIATELY, 
        NULL,
        &pEnumerator);
    
    if (FAILED(hres))
    {
        cout << "Query for processes failed. "
             << "Error code = 0x" 
             << hex << hres << endl;
        pSvc->Release();
        pLoc->Release();     
        CoUninitialize();
        return 1;               // Program has failed.
    }
    else
    { 
        IWbemClassObject *pclsObj;
        ULONG uReturn = 0;
   
        while (pEnumerator)
        {
            hres = pEnumerator->Next(WBEM_INFINITE, 1, 
                &pclsObj, &uReturn);

            if(0 == uReturn)
            {
                break;
            }

            VARIANT vtProp;

            // Get the value of the Name property
            hres = pclsObj->Get(L"Name", 0, &vtProp, 0, 0);
            wcout << "Process Name : " << vtProp.bstrVal << endl;
            VariantClear(&vtProp);
            
            pclsObj->Release();
            pclsObj = NULL;
        }
         
    }
 
    // Cleanup
    // ========
    
    pSvc->Release();
    pLoc->Release();
    pEnumerator->Release();  
    
    CoUninitialize();

    return 0;   // Program successfully completed.
}

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範例：建立 WMI 應用程式

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