c# - 连接到数字秤(Mettler Toledo PS90)作为 HID 仅当电缆首次连接到计算机时运行 On Report

Question

我正在使用 Mike O Brien's HID Library连接到数字秤，设备成功打开，然后完美显示设备附加和删除消息。但最初只运行 OnReport 大约 20 次
Inital 在 OnReport 上运行大约 20 次后，它再也不会运行，除非我拔下 USB 电缆并重新连接。

我的代码在下面

if (scale.IsConnected)
      {
          scale.Inserted += DeviceAttachedHandler;
          scale.Removed += DeviceRemovedHandler;
          scale.MonitorDeviceEvents = true;
          scale.ReadReport(OnReport);
MessageBox.Show("Hold Application Here");

秤的事件处理程序

private void DeviceAttachedHandler()
    {
        MessageBox.Show("Device attached.");
        scale.ReadReport(OnReport);
    }

    private static void DeviceRemovedHandler()
    {
        MessageBox.Show("Device removed.");
    }
    private void OnReport(HidReport report)
    {
        if (!scale.IsConnected) { return; }


        //var cardData = new Data(report.Data);
        decimal weight = Convert.ToDecimal(report.Data[4]);// (Convert.ToDecimal(report.Data[4]) +



        MessageBox.Show(weight.ToString());
//Convert.ToDecimal(report.Data[5]) * 256) / 100;
            //Console.WriteLine(!cardData.Error ? Encoding.ASCII.GetString(cardData.CardData) : cardData.ErrorMessage);
            //Console.WriteLine(report.Data);
        scale.ReadReport(OnReport);
    }

Answer 1

我设法让秤工作，在我的回调中，当秤返回数据时运行，我正在执行 Read，这是一个阻塞调用。因此产生了死锁，应该只使用 ReadReport 或 Read 看看 Mike 在下面发布的示例 here .

using System;
using System.Linq;
using System.Text;
using HidLibrary;

namespace MagtekCardReader
{
    class Program
    {
        private const int VendorId = 0x0801;
        private const int ProductId = 0x0002;

        private static HidDevice _device;

        static void Main()
        {
            _device = HidDevices.Enumerate(VendorId, ProductId).FirstOrDefault();

            if (_device != null)
            {
                _device.OpenDevice();

                _device.Inserted += DeviceAttachedHandler;
                _device.Removed += DeviceRemovedHandler;

                _device.MonitorDeviceEvents = true;

                _device.ReadReport(OnReport);

                Console.WriteLine("Reader found, press any key to exit.");
                Console.ReadKey();

                _device.CloseDevice();
            }
            else
            {
                Console.WriteLine("Could not find reader.");
                Console.ReadKey();
            }
        }

        private static void OnReport(HidReport report)
        {
            if (!_device.IsConnected) { return; }

            var cardData = new Data(report.Data);

            Console.WriteLine(!cardData.Error ? Encoding.ASCII.GetString(cardData.CardData) : cardData.ErrorMessage);

            _device.ReadReport(OnReport);
        }

        private static void DeviceAttachedHandler()
        {
            Console.WriteLine("Device attached.");
            _device.ReadReport(OnReport);
        }

        private static void DeviceRemovedHandler()
        {
            Console.WriteLine("Device removed.");
        }
    }
}