问题描述

VC6.0 获取设备友好名称 （Friendly Name）

VC6.0编写的dll函数用来获取读卡器设备的友好名称，调试中发现当获取设备硬件ID SPDRP_HARDWAREID 时可以取到，但取设备友好名称SPDRP_FRIENDLYNAME时，却为空，代码如下：
int _stdcall GetReaderCardFriendlyName(char *ReaderID)

{
// BOOL iRet = TRUE;
// PDWORD dwBufSize;
DWORD actualSize = 0;
DWORD dwBufSize = 0;

TCHAR dataBuf[MAX_PATH + 1]; // 建立缓冲区以存储设备范例ID；
int len = 0;
int ReaderNum = 0;
GUID ReaderCardClassGuid = {0X50DD5230, 0XBA8A, 0X11D1, {0XBF, 0X5D, 0X00, 0X00, 0Xf8, 0X05, 0Xf5, 0X30}};

//得到一个Class下信息集句柄
m_NewDeviceInfoSet = SetupDiGetClassDevs(&ReaderCardClassGuid, NULL, NULL, DIGCF_PRESENT);   //DIGCF_PRESENT （只列出当前存在的设备信息）
if(m_NewDeviceInfoSet == INVALID_HANDLE_VALUE)
{
   // wprintf(_T("NewDeviceInfoSet == INVALID_HANDLE_VALUE"));
    //bRet = FALSE;
    return -1;
}  

//对得到的此class信息集进行枚举
for(int Device_Index=0; ; Device_Index++)
{
    memset((void*)&(m_ReaderCardDevInfoData), 0, sizeof(SP_DEVINFO_DATA));
    m_ReaderCardDevInfoData.cbSize = sizeof(SP_DEVINFO_DATA);
    BOOL  bResult  = SetupDiEnumDeviceInfo(m_NewDeviceInfoSet, Device_Index, &m_ReaderCardDevInfoData);
    if(bResult == 0)
    {
        if(GetLastError() == ERROR_NO_MORE_ITEMS)
        {
            break;
        }
    //  *pdwBufSize = Required_Size;
    }
    BYTE    *pbReuslt = MySetupDiGetDeviceRegistryProperty(
            SPDRP_FRIENDLYNAME ,   // SPDRP_FRIENDLYNAME SPDRP_HARDWAREID SPDRP_PHYSICAL_DEVICE_OBJECT_NAME
            NULL,&dwBufSize);
    if(pbReuslt)
    {
        TCHAR *tcName = (TCHAR*)pbReuslt;
        free(pbReuslt);
    }
}
//销毁一个Class的device information set
SetupDiDestroyDeviceInfoList(m_NewDeviceInfoSet);
return 0;

}

BYTE* MySetupDiGetDeviceRegistryProperty(
IN DWORD Property,

OUT PDWORD PropertyRegDataType ,

OUT PDWORD pdwBufSize)

{

DWORD Required_Size = 0;

 BOOL bResult = SetupDiGetDeviceRegistryProperty(
                m_NewDeviceInfoSet,
                &m_ReaderCardDevInfoData,
                Property ,
                PropertyRegDataType,
                NULL, 0,
                &Required_Size);
if(!bResult)
{
    if(ERROR_INSUFFICIENT_BUFFER == GetLastError())
    {
        *pdwBufSize = Required_Size;
        BYTE *PropertyBuffer = (BYTE*)malloc(Required_Size);  

        bResult = SetupDiGetDeviceRegistryProperty(
                m_NewDeviceInfoSet,
                &m_ReaderCardDevInfoData,
                Property ,
                PropertyRegDataType,
                PropertyBuffer,
                Required_Size, NULL);
        if(bResult)
            return PropertyBuffer;
        else
        {
            free(PropertyBuffer);
            return NULL;
        }
    }
    else
        return NULL;
}
else
    return NULL;

}

解决方案

如果设备没有提供名称信息，就会返回空