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请参阅下面的编辑。

我正在尝试获取已连接设备（例如电视或投影仪）的类/接口 GUID。我正在使用函数 RegisterDeviceNotification() 在连接电视时为我提供 GUID。

我的问题：连接电视后，我可以成功收到通知，但是当我访问设备的 GUID（通过检查 lParam 结构）时，我收到访问冲突或错误。

我无法弄清楚出了什么问题？每当我访问或使用 GUID 时，我的程序都会失败，请注意我的程序不会崩溃，但输出窗口会写出类似的First-chance exception at 0x001c1a9d in myProgram.exe...内容，但我无法弄清楚出了什么问题？

HDEVNOTIFY *hDeviceNotify;
GUID interfaceClassGuid = { 0x25dbce51, 0x6c8f, 0x4a72, 0x8a,0x6d,0xb5,0x4c,0x2b,0x4f,0xc8,0x35 };
LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    int wmId, wmEvent;
    PAINTSTRUCT ps;
    HDC hdc;

    switch (message)
    {
        case WM_CREATE:
        {                  
             openConsoleWindow();

             DEV_BROADCAST_DEVICEINTERFACE NotificationFilter;
             ZeroMemory( &NotificationFilter, sizeof(NotificationFilter) );
             NotificationFilter.dbcc_size       = sizeof(DEV_BROADCAST_DEVICEINTERFACE);
             NotificationFilter.dbcc_devicetype = DBT_DEVTYP_DEVICEINTERFACE;
             NotificationFilter.dbcc_classguid  = interfaceClassGuid;

             *hDeviceNotify = RegisterDeviceNotification( hWnd, &NotificationFilter, DEVICE_NOTIFY_WINDOW_HANDLE );

             if (*hDeviceNotify == NULL)
                 printf("hDeviceNotify = NULL \n");
        }    
        break;
        case WM_DEVICECHANGE:
        {
            PDEV_BROADCAST_DEVICEINTERFACE b = (PDEV_BROADCAST_DEVICEINTERFACE) lParam;

            // The following printf NEVER prints out. 
            // When accessing the below GUID I get an error:
            // "First-chance exception at 0x001c1a9d in myProgram.exe: 0xC0000005: Access violation writing location 0x00000000."
            printf("GUID: Data1: %x, Data2: %x, Data3: %x, Data4: %s \n", b->dbcc_classguid.Data1,
                b->dbcc_classguid.Data2, b->dbcc_classguid.Data3, (char*)b->dbcc_classguid.Data4);

            // The following function ALWAYS fails.
            // GetLastError() gives the error "The parameter is incorrect"
            HDEVINFO hDevInfo = SetupDiGetClassDevs(&b->dbcc_classguid, NULL, NULL, DIGCF_PRESENT | DIGCF_DEVICEINTERFACE);
            if (hDevInfo == INVALID_HANDLE_VALUE) {
               //printf("hDevInfo == INVALID_HANDLE_VALUE \n");
               outputLastError(_T("hDevInfo == INVALID_HANDLE_VALUE \n"));
            }

        }
        break;
        ...

编辑：我已经应用了 Hans 的建议，但仍然出现同样的问题（printf() 从不打印并且发生异常）：

        case WM_DEVICECHANGE:
        {
            if (wParam != DBT_DEVNODES_CHANGED) {
                printf("1: \n");
                break;
            }

            PDEV_BROADCAST_HDR h = (PDEV_BROADCAST_HDR) lParam;
            if (h->dbch_devicetype != DBT_DEVTYP_DEVICEINTERFACE) {
                printf("2\n");
                break;
            }

            PDEV_BROADCAST_DEVICEINTERFACE b = (PDEV_BROADCAST_DEVICEINTERFACE) h;

            // When accessing the below GUID I get an error:
            // "First-chance exception at 0x001c1a9d in TEST GUID Error.exe: 0xC0000005: Access violation writing location 0x00000000."
            printf("GUID: Data1: %x, Data2: %x, Data3: %x, Data4: %s \n", b->dbcc_classguid.Data1,
                b->dbcc_classguid.Data2, b->dbcc_classguid.Data3, (char*)b->dbcc_classguid.Data4);

            // The following function ALWAYS fails.
            // GetLastError() gives the error "The parameter is incorrect"
            HDEVINFO hDevInfo = SetupDiGetClassDevs(&b->dbcc_classguid, NULL, NULL, DIGCF_PRESENT | DIGCF_DEVICEINTERFACE);
            if (hDevInfo == INVALID_HANDLE_VALUE) {
               //printf("hDevInfo == INVALID_HANDLE_VALUE \n");
               outputLastError(_T("hDevInfo == INVALID_HANDLE_VALUE \n"));
            }

        }
        break;
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