问题描述

求大神帮忙！　WriteFile 写入长度只能为9 什么7啊 8啊 10啊都报错！

之前下资料币用完了 ！ 好人全家幸福 一生平安
DevHID::DevHID(WORD vid WORD pid)
{
if (GetDevicePath(vid pid))
{
writeHandle = CreateFile(devDetail->DevicePath
GENERIC_WRITE | GENERIC_READ
FILE_SHARE_READ | FILE_SHARE_WRITE
NULL
OPEN_EXISTING
FILE_ATTRIBUTE_NORMAL | FILE_FLAG_OVERLAPPED
NULL);

    if (writeHandle == INVALID_HANDLE_VALUE)    {        cout << ""创建写句柄失败！"" << endl;    }    readHandle = CreateFile(devDetail->DevicePath        GENERIC_WRITE | GENERIC_READ        FILE_SHARE_READ | FILE_SHARE_WRITE        NULL        OPEN_EXISTING        FILE_ATTRIBUTE_NORMAL | FILE_FLAG_OVERLAPPED        NULL);    if (readHandle == INVALID_HANDLE_VALUE)    {        cout << ""创建读句柄失败！"" << endl;    }}else{    cout << ""获取设备路径失败！"" << endl;}

}

BOOL DevHID::GetDevicePath(DWORD VID DWORD PID)
{
HDEVINFO hDevInfo; // 设备信息结构
GUID hidGuid; // 设备接口类

ULONG  requiredLength;        //  指定接受缓冲区大小；  //  设备句柄HANDLE hidHandle;//  用于接受VID PID_HIDD_ATTRIBUTES hidAttributes;//  获取符合条件的设备信息HidD_GetHidGuid(&hidGuid);//  获得信息hDevInfo = SetupDiGetClassDevs(    &hidGuid    NULL    NULL    (DIGCF_PRESENT | DIGCF_DEVICEINTERFACE));if (hDevInfo == INVALID_HANDLE_VALUE){    return FALSE;  //  错误返回}SP_DEVICE_INTERFACE_DATA devInfoData;       //  设备信息集合devInfoData.cbSize = sizeof(SP_DEVICE_INTERFACE_DATA);for (int deviceNo = 0; deviceNo < 20; deviceNo++){    //  枚举设备    if (!SetupDiEnumInterfaceDevice(        hDevInfo        &hidGuid        deviceNo        &devInfoData))    {        //  错误返回        SetupDiDestroyDeviceInfoList(hDevInfo);        return FALSE;     }    //   获得缓冲区大小    SetupDiGetInterfaceDeviceDetail(hDevInfo        &devInfoData        NULL        &requiredLength // 接受缓冲区大小        NULL);    //  根据返回的信息分配缓冲区大小    devDetail = (PSP_INTERFACE_DEVICE_DETAIL_DATA)malloc(requiredLength);    //  指定大小    devDetail->cbSize = sizeof(SP_INTERFACE_DEVICE_DETAIL_DATA);    //  填充设备路径信息缓冲区    if (!SetupDiGetInterfaceDeviceDetail(hDevInfo        &devInfoData        devDetail        requiredLength        NULL        NULL))    {        SetupDiDestroyDeviceInfoList(hDevInfo);        free(devDetail);        return FALSE;    }    //  打开设备    hidHandle = CreateFile(devDetail->DevicePath        NULL        FILE_SHARE_READ | FILE_SHARE_WRITE        NULL        OPEN_EXISTING        FILE_ATTRIBUTE_NORMAL        NULL);    if (hidHandle == INVALID_HANDLE_VALUE)    {        //　失败        SetupDiDestroyDeviceInfoList(hDevInfo);        CloseHandle(hidHandle);        free(devDetail);        return FALSE;    }    if (!HidD_GetAttributes(hidHandle &hidAttributes))    {        //  获得失败        SetupDiDestroyDeviceInfoList(hDevInfo);        CloseHandle(hidHandle);        free(devDetail);        return FALSE;    }    if ((VID == hidAttributes.VendorID  &&         PID == hidAttributes.ProductID))    {        //  匹配并退出        SetupDiDestroyDeviceInfoList(hDevInfo);        CloseHandle(hidHandle);        return TRUE;    }}SetupDiDestroyDeviceInfoList(hDevInfo);CloseHandle(hidHandle);return FALSE;

}

OVERLAPPED WriteOverlapped;
WriteOverlapped.Offset = 0;
WriteOverlapped.OffsetHigh = 0;

WriteOverlapped.hEvent = CreateEvent(NULL TRUE FALSE NULL);char WriteReportBuffer[64];WriteReportBuffer[0] = 0x00;    WriteReportBuffer[1] = 0x10;WriteReportBuffer[2] = 0x20;WriteReportBuffer[3] = 0x30;WriteReportBuffer[4] = 0x40;WriteReportBuffer[5] = 0x30;WriteReportBuffer[6] = 0x40;WriteFile(writeHandle    WriteReportBuffer    NULL    &WriteOverlapped);cout << ""CODE:"" << GetLastError() << endl;switch (WaitForSingleObject(WriteOverlapped.hEvent 2000)){case WAIT_OBJECT_0:    cout << "" 函数返回成功！"" << endl;    return;case WAIT_TIMEOUT:    cout << "" 间隔时间到！"" << endl;    return;case WAIT_FAILED:    cout << ""WaitForSingleObject 失败！"" << endl;    return;default:    cout << ""什么也没有做！"" << endl;}

解决方案

你的方法调用没有问题，第三个参数表示需要将缓冲区中多少字节的数据写入问题，只要这个值不超过缓冲区的长度，应该是没有问题的。
你调用不是9时报的错误信息是什么呢？