Question

I am trying to create an executable that can be called and pass back a weight from a Fairbanks SCB-9000 USB scale. I have found some code that was for a different model scale, but it is not quite working for me. I am specifically having an issue with the following method. It is giving me an error: “Cannot Implicity Convert Type ‘System.Collections.Generic.IEnumerable’ to ‘HidLibrary.HidDevice[]’.” I have tried several ways of casting this, but I can’t get it to work. Any suggestions here, or has anyone ever written any code for this particular scale?

Thank you,

Rob

Here is the method in question:

    public HidDevice[] GetDevices()
    {
        HidDevice[] hidDeviceList;

        // Fairbanks Scale
        hidDeviceList = HidDevices.Enumerate(0x0B67, 0x555E);

        if (hidDeviceList.Length > 0)

            return hidDeviceList;

    }

Sorry should have added that I am using Mike Obrien’s HidLibrary from here: http://nuget.org/packages/hidlibrary

UPDATE WITH FULL CODE…

Here is the code that I am using…

program.cs

using System;
using System.Threading;
using HidLibrary;
using Scale;

namespace ScaleReader
{
    class Program
    {
        public static void Main(string[] args)
        {
            decimal? weight;
            bool? isStable;

            USBScale s = new USBScale();
            s.Connect();

            if (s.IsConnected)
            {
                s.GetWeight(out weight, out isStable);
                s.DebugScaleData();
                Console.WriteLine("Weight: {0:0.00} LBS", weight);
            }
            else
            {
                Console.WriteLine("No Scale Connected.");
            }

            s.Disconnect();
            Thread.Sleep(500);
        }
    }
}

Scale.cs

using HidLibrary;
using System.Threading;
using System;
using System.Collections.Generic;
using System.Text;

namespace Scale
{
    class USBScale
    {
        public bool IsConnected
        {
            get
            {
                return scale == null ? false : scale.IsConnected;
            }
        }
        public decimal ScaleStatus
        {
            get
            {
                return inData.Data[1];
            }
        }
        public decimal ScaleWeightUnits
        {
            get
            {
                return inData.Data[2];
            }
        }
        private HidDevice scale;
        private HidDeviceData inData;

public HidDevice[] GetDevices() 
{ 
    return HidDevices.Enumerate(0x0B67, 0x555E).Cast<HidDevice>().ToArray(); 
} 

        public bool Connect()
        {
            // Find a Scale
            HidDevice[] deviceList = GetDevices();

            if (deviceList.Length > 0)

                return Connect(deviceList[0]);

            else

                return false;
        }
        public bool Connect(HidDevice device)
        {
            scale = device;
            int waitTries = 0;
            scale.OpenDevice();

            // sometimes the scale is not ready immedietly after
            // Open() so wait till its ready
            while (!scale.IsConnected && waitTries < 10)
            {
                Thread.Sleep(50);
                waitTries++;
            }
            return scale.IsConnected;
        }
        public void Disconnect()
        {
            if (scale.IsConnected)
            {
                scale.CloseDevice();
                scale.Dispose();
            }
        }
        public void DebugScaleData()
        {
            for (int i = 0; i < inData.Data.Length; ++i)
            {
                Console.WriteLine("Byte {0}: {1}", i, inData.Data[i]);
            }
        }
        public void GetWeight(out decimal? weight, out bool? isStable)
        {
            weight = null;
            isStable = false;

            if (scale.IsConnected)
            {
                inData = scale.Read(250);
                // Byte 0 == Report ID?
                // Byte 1 == Scale Status (1 == Fault, 2 == Stable @ 0, 3 == In Motion, 4 == Stable, 5 == Under 0, 6 == Over Weight, 7 == Requires Calibration, 8 == Requires Re-Zeroing)
                // Byte 2 == Weight Unit
                // Byte 3 == Data Scaling (decimal placement)
                // Byte 4 == Weight LSB
                // Byte 5 == Weight MSB

                // FIXME: dividing by 100 probably wont work with
                // every scale, need to figure out what to do with
                // Byte 3
                weight = (Convert.ToDecimal(inData.Data[4]) +
                    Convert.ToDecimal(inData.Data[5]) * 256) / 100;

                switch (Convert.ToInt16(inData.Data[2]))
                {
                    case 3:  // Kilos
                        weight = weight * (decimal?)2.2;
                        break;
                    case 11: // Ounces
                        weight = weight * (decimal?)0.625;
                        break;
                    case 12: // Pounds
                        // already in pounds, do nothing
                        break;
                }
                isStable = inData.Data[1] == 0x4;
            }
        }
    }
}

Answer 1

What you have won’t compile since you don’t always return something. Based on the error message, this is all you really need. I can’t find any reference for HidDevice or HidDevices so I can’t say this will work with absolute certainty.

public HidDevice[] GetDevices()
{
    return HidDevices.Enumerate(0x0B67, 0x555E).Cast<HidDevice>().ToArray();
}

You’ll have to add this line for it to compile:

using System.Linq;

---

As a side-note, get ReSharper.