USB 设备插拔事件处理

        Windows 系统下，设备连接至电脑或从电脑移除，系统会广播一条 WM_DEVICECHANGE 消息到所有应用程序，在程序的消息处理函数中可以对事件进行相应。

class CMainDlg : public CDialogImpl<CMainDlg> {
public:
    enum { IDD = IDD_MAINDLG };

    BEGIN_MSG_MAP(CMainDlg)
        ......
        MESSAGE_HANDLER(WM_DEVICECHANGE, OnDeviceChange)
    END_MSG_MAP()

    LRESULT OnDeviceChange(UINT uMsg, WPARAM wParam, LPARAM lParam, BOOL& bHandled) {
        if(wParam == DBT_DEVICEARRIVAL) {
            PDEV_BROADCAST_HDR pHdr = (PDEV_BROADCAST_HDR)lParam;
            if(pHdr->dbch_devicetype == DBT_DEVTYP_DEVICEINTERFACE) {
                PDEV_BROADCAST_DEVICEINTERFACE pDevInf = (PDEV_BROADCAST_DEVICEINTERFACE)pHdr;
                CString dbcc_name = pDevInf->dbcc_name;
                if(dbcc_name.Find(_T("VID_xxxx&PID_xxxx")) != -1) {
                    MessageBox("特定设备已插入");
                }
            }
        } else if(wParam == DBT_DEVICEREMOVECOMPLETE) {
            PDEV_BROADCAST_HDR pHdr = (PDEV_BROADCAST_HDR)lParam;
            if(pHdr->dbch_devicetype == DBT_DEVTYP_DEVICEINTERFACE) {
                PDEV_BROADCAST_DEVICEINTERFACE pDevInf = (PDEV_BROADCAST_DEVICEINTERFACE)pHdr;
                CString dbcc_name = pDevInf->dbcc_name;
                if(dbcc_name.Find(_T("Ven_USBKey&Prod_USBKey")) != -1) {
                    MessageBox("特定设备已拔出");
                }
            }
        }
        return 0;
    }
}