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文章目录
  1. 1. 简单介绍
  2. 2. 例子

简单介绍

本篇介绍如何用C++编程做出检查USB设备的插拔状态以及读取相关信息的一个小工具。
毕业工作被安排的第一个任务就是做要用C或C++的关于硬件类的。都不是太熟且对硬件类不太感兴趣，但没办法还是得硬着头皮上。网上关于USB插拔的倒是有一点小例子，但是要读出USB设备信息的例子却很少。好不容易找到一个却是用MFC做的，而以前也从没用过C的MFC编程，生搬硬套最后还是做出了这种控制台显示USB插拔状态及设备信息的小工具。

例子

以下贴出其中一些核心代码，代码有些具体的地方还不怎么懂，以后熟悉了好好研究。

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// Compute Device Class: this is used to get the tree contrl root icon
static const GUID GUID_DEVCLASS_COMPUTER =
{ 0x4D36E966, 0xE325, 0x11CE, { 0xBF, 0xC1, 0x08, 0x00, 0x2B, 0xE1, 0x03, 0x18 } };

// Copy from HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\DeviceClasses
static const GUID GUID_DEVINTERFACE_LIST[] =
{
	// GUID_DEVINTERFACE_USB_DEVICE
	{ 0xA5DCBF10, 0x6530, 0x11D2, { 0x90, 0x1F, 0x00, 0xC0, 0x4F, 0xB9, 0x51, 0xED } },

	// GUID_DEVINTERFACE_DISK
	{ 0x53f56307, 0xb6bf, 0x11d0, { 0x94, 0xf2, 0x00, 0xa0, 0xc9, 0x1e, 0xfb, 0x8b } },

	// GUID_DEVINTERFACE_HID, 
	{ 0x4D1E55B2, 0xF16F, 0x11CF, { 0x88, 0xCB, 0x00, 0x11, 0x11, 0x00, 0x00, 0x30 } },

	// GUID_NDIS_LAN_CLASS
	{ 0xad498944, 0x762f, 0x11d0, { 0x8d, 0xcb, 0x00, 0xc0, 0x4f, 0xc3, 0x35, 0x8c } }

	//// GUID_DEVINTERFACE_COMPORT
	//{ 0x86e0d1e0, 0x8089, 0x11d0, { 0x9c, 0xe4, 0x08, 0x00, 0x3e, 0x30, 0x1f, 0x73 } },

	//// GUID_DEVINTERFACE_SERENUM_BUS_ENUMERATOR
	//{ 0x4D36E978, 0xE325, 0x11CE, { 0xBF, 0xC1, 0x08, 0x00, 0x2B, 0xE1, 0x03, 0x18 } },

	//// GUID_DEVINTERFACE_PARALLEL
	//{ 0x97F76EF0, 0xF883, 0x11D0, { 0xAF, 0x1F, 0x00, 0x00, 0xF8, 0x00, 0x84, 0x5C } },

	//// GUID_DEVINTERFACE_PARCLASS
	//{ 0x811FC6A5, 0xF728, 0x11D0, { 0xA5, 0x37, 0x00, 0x00, 0xF8, 0x75, 0x3E, 0xD1 } }
};

查找是否有设备

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BOOL FindDevice(HDEVINFO& hDevInfo,
	CString& szDevId,
	SP_DEVINFO_DATA& spDevInfoData){

	spDevInfoData.cbSize = sizeof(SP_DEVINFO_DATA);
	for (int i = 0; SetupDiEnumDeviceInfo(hDevInfo, i, &spDevInfoData); i++) {
		DWORD nSize = 0;
		TCHAR buf[MAX_PATH];

		if (!SetupDiGetDeviceInstanceId(hDevInfo, &spDevInfoData, buf, sizeof(buf), &nSize)) {
		
			return FALSE;
		}
		if (szDevId == buf) {
			// OK, device found
			return TRUE;
		}
	}
	return FALSE;
}

更新设备信息，打印输出。

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void UpdateDevice(PDEV_BROADCAST_DEVICEINTERFACE pDevInf, WPARAM wParam){
	// pDevInf->dbcc_name: 
	// \\?\USB#Vid_04e8&Pid_503b#0002F9A9828E0F06#{a5dcbf10-6530-11d2-901f-00c04fb951ed}
	// szDevId: USB\Vid_04e8&Pid_503b\0002F9A9828E0F06
	// szClass: USB
	CString szDevId = pDevInf->dbcc_name + 4;
	//cout << szDevId.GetBuffer() << "hello" << endl;
	int idx = szDevId.ReverseFind(_T('#'));
	szDevId.Truncate(idx);
	szDevId.Replace(_T('#'), _T('\\'));
	szDevId.MakeUpper();
	CString szClass;

	idx = szDevId.Find(_T('\\'));
	szClass = szDevId.Left(idx);

	if (DBT_DEVICEARRIVAL == wParam) {
		//cout << "Adding " << szDevId.GetBuffer() << endl;//szDevId输入框设备信息
		insert = true;
	}
	else {
		//cout << "Removing " << szDevId.GetBuffer() << endl;
		insert = false;

	}


	DWORD dwFlag = DBT_DEVICEARRIVAL != wParam ?
	DIGCF_ALLCLASSES : (DIGCF_ALLCLASSES | DIGCF_PRESENT);
	HDEVINFO hDevInfo = SetupDiGetClassDevs(NULL, szClass, NULL, dwFlag);

	if (INVALID_HANDLE_VALUE == hDevInfo) {
		
		return;
	}

	SP_DEVINFO_DATA spDevInfoData;
	

	if (FindDevice(hDevInfo, szDevId, spDevInfoData)){

		DWORD DataT;
		TCHAR buf[MAX_PATH];
		DWORD nSize = 0;

		// get Friendly Name or Device Description
		if (SetupDiGetDeviceRegistryProperty(hDevInfo, &spDevInfoData,
			SPDRP_FRIENDLYNAME, &DataT, (PBYTE)buf, sizeof(buf), &nSize)) {
		}
		else if (SetupDiGetDeviceRegistryProperty(hDevInfo, &spDevInfoData,
			SPDRP_DEVICEDESC, &DataT, (PBYTE)buf, sizeof(buf), &nSize)) {
		}
		else {
			lstrcpy(buf, _T("Unknown"));
		}

		// remove device
		BOOL bFound = FALSE;
		szDevId.Replace(_T('\\'), _T('#'));
		if (insert){
			cout << "usb_connected@" << szDevId<<"$"<<buf << endl;
		}
		else{
			cout << "usb_disconnected@" << szDevId<<"$"<< buf << endl;
		}
	}
	
}

判断设备类型

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LRESULT CALLBACK WndProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
{
	if (DBT_DEVICEARRIVAL == wParam || DBT_DEVICEREMOVECOMPLETE == wParam) {
		PDEV_BROADCAST_HDR pHdr = (PDEV_BROADCAST_HDR)lParam;
		PDEV_BROADCAST_DEVICEINTERFACE pDevInf;
		PDEV_BROADCAST_HANDLE pDevHnd;
		PDEV_BROADCAST_OEM pDevOem;
		PDEV_BROADCAST_PORT pDevPort;
		PDEV_BROADCAST_VOLUME pDevVolume;
		switch (pHdr->dbch_devicetype) {
		case DBT_DEVTYP_DEVICEINTERFACE:
			pDevInf = (PDEV_BROADCAST_DEVICEINTERFACE)pHdr;
			UpdateDevice(pDevInf, wParam);
			break;
		case DBT_DEVTYP_HANDLE:
			pDevHnd = (PDEV_BROADCAST_HANDLE)pHdr;
			break;

		case DBT_DEVTYP_OEM:
			pDevOem = (PDEV_BROADCAST_OEM)pHdr;
			break;

		case DBT_DEVTYP_PORT:
			pDevPort = (PDEV_BROADCAST_PORT)pHdr;
			break;

		case DBT_DEVTYP_VOLUME:
			pDevVolume = (PDEV_BROADCAST_VOLUME)pHdr;
			break;
		}
	}
	return DefWindowProc(hWnd, uMsg, wParam, lParam);
}

主函数

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int  main(int argc, TCHAR* argv[], TCHAR* envp[])
{

	TCHAR szClassName[] = _T("MyApp");
	WNDCLASS wndcls = { 0 };
	wndcls.hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH);
	wndcls.hCursor = (HCURSOR)LoadCursor(NULL, IDC_ARROW);
	wndcls.hIcon = (HICON)LoadIcon(NULL, IDI_APPLICATION);
	wndcls.lpfnWndProc = WndProc;
	wndcls.lpszClassName = szClassName;

	if (!RegisterClass(&wndcls))
	{
		printf("RegisterClass Failed!\r\n");
		return 0;
	}

	HWND hWnd = CreateWindow(szClassName, szClassName, WS_OVERLAPPEDWINDOW, CW_USEDEFAULT,
		CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, NULL, NULL, NULL, NULL);
	if (NULL == hWnd)
	{
		printf("CreateWindow Failed!\r\n");
		return 0;
	}

	ShowWindow(hWnd, SW_HIDE);
	UpdateWindow(hWnd);

	//printf("WM_DEVICECHANGE=%d\n", WM_DEVICECHANGE);
	//printf("显示USB设备插拔变动信息：\n");

	HDEVNOTIFY hDevNotify;
	DEV_BROADCAST_DEVICEINTERFACE NotificationFilter;
	ZeroMemory(&NotificationFilter, sizeof(NotificationFilter));
	NotificationFilter.dbcc_size = sizeof(DEV_BROADCAST_DEVICEINTERFACE);
	NotificationFilter.dbcc_devicetype = DBT_DEVTYP_DEVICEINTERFACE;
	for (int i = 0; i<sizeof(GUID_DEVINTERFACE_LIST) / sizeof(GUID); i++) {
		NotificationFilter.dbcc_classguid = GUID_DEVINTERFACE_LIST[i];
		hDevNotify = RegisterDeviceNotification(hWnd, &NotificationFilter, DEVICE_NOTIFY_WINDOW_HANDLE);
		if (!hDevNotify) {
			printf("Can't register device notification");
			return FALSE;
		}
	}

	MSG msg;
	while (GetMessage(&msg, NULL, NULL, NULL))
	{
		TranslateMessage(&msg);
		DispatchMessage(&msg);
	}

	return 0;
}

运行结果如图

算法
算法
文章目录
  1. 1. 简单介绍
  2. 2. 例子