列舉服務

WpdServicesApiSample 應用程式包含程式碼，示範應用程式如何列舉目前連線到電腦之任何裝置上找到的所有連絡人服務。

當使用者在命令列選擇選項 「0」 時，應用程式會叫用 ServiceEnumeration.cpp 模組中找到的 EnumerateContactsServices 方法。 這個方法會顯示支援連絡人服務的所有已連線裝置清單。

例如，如果 WpdServiceSampleDriver 是唯一安裝的裝置，應用程式會傳回三個資料欄位：易記名稱 (「範例裝置」) 、製造商 (「Windows 可攜式裝置群組」) ，以及描述 (「連絡人服務裝置 2000」) 。

EnumerateContactsServices方法會完成下列工作：

• 建立 IPortableDeviceManager 介面來處理已安裝裝置的列舉。
• 建立 IPortableDeviceServiceManager 介面，以處理每個裝置上的服務列舉。
• 逐一查看已安裝的裝置、搜尋連絡人服務，並顯示支援此服務之任何裝置的裝置資訊。

下列程式碼說明 EnumerateContactsServices 方法。

// Enumerates all Contacts Services, displaying the associated device of each service.
void EumerateContactsServices(CAtlArray<PWSTR>& ContactsServicePnpIDs)
{
    HRESULT                                 hr              = S_OK;
    DWORD                                   cPnpDeviceIDs   = 0;
    PWSTR*                                  pPnpDeviceIDs   = NULL;
    CComPtr<IPortableDeviceManager>         pPortableDeviceManager;
    CComPtr<IPortableDeviceServiceManager>  pServiceManager;

    // CoCreate the IPortableDeviceManager interface to enumerate
    // portable devices and to get information about them.
    hr = CoCreateInstance(CLSID_PortableDeviceManager,
                          NULL,
                          CLSCTX_INPROC_SERVER,
                          IID_PPV_ARGS(&pPortableDeviceManager));

    if (FAILED(hr))
    {
        printf("! Failed to CoCreateInstance CLSID_PortableDeviceManager, hr = 0x%lx\n",hr);
    }        

    // Retrieve the IPortableDeviceServiceManager interface to enumerate device services.
    if (SUCCEEDED(hr))
    {
        hr = pPortableDeviceManager->QueryInterface(IID_PPV_ARGS(&pServiceManager));
        if (FAILED(hr))
        {
            printf("! Failed to QueryInterface IID_IPortableDeviceServiceManager, hr = 0x%lx\n",hr);
        }
    }

    if (SUCCEEDED(hr))
    {
        // First, pass NULL as the PWSTR array pointer to get the total number
        // of devices found on the system.
        hr = pPortableDeviceManager->GetDevices(NULL, &cPnpDeviceIDs);

        if (FAILED(hr))
        {
            printf("! Failed to get number of devices on the system, hr = 0x%lx\n",hr);
        }

        if (SUCCEEDED(hr) && (cPnpDeviceIDs > 0))
        {
            // Second, allocate an array to hold the PnPDeviceID strings returned from
            // the IPortableDeviceManager::GetDevices method
            pPnpDeviceIDs = new (std::nothrow) PWSTR[cPnpDeviceIDs];

            if (pPnpDeviceIDs != NULL)
            {
                DWORD dwIndex = 0;

                hr = pPortableDeviceManager->GetDevices(pPnpDeviceIDs, &cPnpDeviceIDs);
                if (SUCCEEDED(hr))
                {   
                    // For each device found, find the contacts service
                    for (dwIndex = 0; dwIndex < cPnpDeviceIDs; dwIndex++)
                    {
                        DWORD   cPnpServiceIDs = 0;
                        PWSTR   pPnpServiceID  = NULL;

                        // First, pass NULL as the PWSTR array pointer to get the total number
                        // of contacts services (SERVICE_Contacts) found on the device.
                        // To find the total number of all services on the device, use GUID_DEVINTERFACE_WPD_SERVICE.
                        hr = pServiceManager->GetDeviceServices(pPnpDeviceIDs[dwIndex], SERVICE_Contacts, NULL, &cPnpServiceIDs);
                        
                        if (SUCCEEDED(hr) && (cPnpServiceIDs > 0))
                        {                               
                            // For simplicity, we are only using the first contacts service on each device
                            cPnpServiceIDs = 1;
                            hr = pServiceManager->GetDeviceServices(pPnpDeviceIDs[dwIndex], SERVICE_Contacts, &pPnpServiceID, &cPnpServiceIDs);

                            if (SUCCEEDED(hr))
                            {
                                // We've found the service, display it and save its PnP Identifier
                                ContactsServicePnpIDs.Add(pPnpServiceID);

                                printf("[%d] ", static_cast<DWORD>(ContactsServicePnpIDs.GetCount()-1));

                                // Display information about the device that contains this service.
                                DisplayDeviceInformation(pServiceManager, pPnpServiceID);

                                // ContactsServicePnpIDs now owns the memory for this string
                                pPnpServiceID = NULL;
                            }
                            else
                            {
                                printf("! Failed to get the first contacts service from '%ws, hr = 0x%lx\n",pPnpDeviceIDs[dwIndex],hr);
                            }
                        }
                    }
                }

                // Free all returned PnPDeviceID strings
                FreePortableDevicePnPIDs(pPnpDeviceIDs, cPnpDeviceIDs);

                // Delete the array of PWSTR pointers
                delete [] pPnpDeviceIDs;
                pPnpDeviceIDs = NULL;

            }
            else
            {
                printf("! Failed to allocate memory for PWSTR array\n");
            }            
        }
    }
    
    printf("\n%d Contacts Device Service(s) found on the system\n\n", static_cast<DWORD>(ContactsServicePnpIDs.GetCount()));
}

相關主題

IPortableDeviceManager 介面

IPortableDeviceServiceManager 介面

WpdServicesApiSample