使用DataWrite :: DetachBuffer发生错误（WinRT C ++）

Posted 2021-04-13

auto featureReport = hidDevice-> CreateFeatureReport（6）; auto dataWriter = ref new DataWriter（）;

Array<UINT8>^buff = ref new Array<UINT8>(6);

buff[0] = (uint8)featureReport->Id;
buff[1] = 0xe;//update mode
buff[2] = 0;
buff[3] = 0;
buff[4] = 0;
buff[5] = 0;

dataWriter->WriteBytes(buff);
featureReport->Data = dataWriter->DetachBuffer();

create_task(hidDevice->SendFeatureReportAsync(featureReport))
    .then([this](task<uint32> bytesWrittenTask)
{
    auto x = bytesWrittenTask.get();    // If exception occured, let an exception flow down the task chain so it can be caught

    //MessageDialog^ msg = ref new MessageDialog(x.ToString());
});

这段代码是在成功之后访问hid驱动程序需要向hid设备发送命令，但这里的错误featureReport-> Data = dataWriter-> DetachBuffer（）;错误消息：HRESULT：0x80070057参数错误

答案

您可能正在达到无效的缓冲区长度。在尝试写入之前尝试获取缓冲区长度。

(pseudo code)
FeatureReport report = hidDevice->GetFeatureReport(reportId)
Array<UINT8>^buff = ref new Array<UINT8>(report.Data.Length);