c# program that reading from usb

Question

Hi this is program for my graduation project that read from usb but even i connect usb to computer it gives me every time "Device can't found" please help me

the code:

namespace Grad_pro
{
    public class read_data
    {
        public static UsbDevice MyUsbDevice;

        #region SET YOUR USB Vendor and Product ID!

        public static UsbDeviceFinder MyUsbFinder =
            new UsbDeviceFinder(0x0000, 0x0000); // specify vendor, product id

        #endregion

        public static void Main(string[] args)
        {
            ErrorCode ec = ErrorCode.None;

            try
            {
                // Find and open the usb device.
                MyUsbDevice = UsbDevice.OpenUsbDevice(MyUsbFinder);

                // If the device is open and ready
                if (MyUsbDevice == null) throw new Exception("Device Not Found.");

                // If this is a "whole" usb device (libusb-win32, linux libusb)
                // it will have an IUsbDevice interface. If not (WinUSB) the
                // variable will be null indicating this is an interface of a
                // device.
                IUsbDevice wholeUsbDevice = MyUsbDevice as IUsbDevice;
                if (!ReferenceEquals(wholeUsbDevice, null))
                {
                    // This is a "whole" USB device. Before it can be used,
                    // the desired configuration and interface must be selected.

                    // Select config
                    wholeUsbDevice.SetConfiguration(1);

                    // Claim interface
                    wholeUsbDevice.ClaimInterface(1);
                }

                // open read endpoint
                UsbEndpointReader reader =
                    MyUsbDevice.OpenEndpointReader(ReadEndpointID.Ep02);

                // open write endpoint
                UsbEndpointWriter writer =
                    MyUsbDevice.OpenEndpointWriter(WriteEndpointID.Ep03);

                // write data, read data
                int bytesWritten;
                ec = writer.Write(new byte[] { 0x00, 0x00 }, 2000, out bytesWritten); // specify data to send

                if (ec != ErrorCode.None)
                    throw new Exception(UsbDevice.LastErrorString);

                byte[] readBuffer = new byte[1024];
                while (ec == ErrorCode.None)
                {
                    int bytesRead;

                    // If the device hasn't sent data in the last 100 milliseconds,
                    // a timeout error (ec = IoTimedOut) will occur.
                    ec = reader.Read(readBuffer, 100, out bytesRead);

                    if (bytesRead == 0) throw new Exception("No more bytes!");

                    // Write that output to the console.
                    Console.WriteLine(BitConverter.ToString(readBuffer, 0, bytesRead));
                }

                Console.WriteLine("\r\nDone!\r\n");
            }
            catch (Exception ex)
            {
                Console.WriteLine();
                Console.WriteLine((ec != ErrorCode.None ? ec + ":" : String.Empty) + ex.Message);
            }
            finally
            {
                if (MyUsbDevice != null)
                {
                    if (MyUsbDevice.IsOpen)
                    {
                        // If this is a "whole" usb device (libusb-win32, linux libusb-1.0)
                        // it exposes an IUsbDevice interface. If not (WinUSB) the
                        // 'wholeUsbDevice' variable will be null indicating this is
                        // an interface of a device; it does not require or support
                        // configuration and interface selection.
                        IUsbDevice wholeUsbDevice = MyUsbDevice as IUsbDevice;
                        if (!ReferenceEquals(wholeUsbDevice, null))
                        {
                            // Release interface
                            wholeUsbDevice.ReleaseInterface(1);
                        }

                        MyUsbDevice.Close();
                    }
                    MyUsbDevice = null;

                    // Free usb resources
                    UsbDevice.Exit();

                }

                // Wait for user input..
                Console.ReadKey();
            }
        }
    }
}

Possible duplicate of [Get List of connected USB Devices](http://stackoverflow.com/questions/3331043/get-list-of-connected-usb-devices) — Max von Hippel, Mar 15 '16 at 19:06

score 0 · Answer 1 · answered Jan 01 '19 at 21:15

The LibUsbDotNet library appears to be undergoing some change at the moment. I had no luck with getting any of the older versions of the library to work. However, there is an alpha version that does work. I submitted this sample to them and it was accepted. It works for the device I am talking to (as long as you add a physical reference to the libusb dll.

However, I don't recommend using LibUsb. LibUSb is just a C wrapper for the standard Windows USB and Hid API calls. This is useful if you want somethign cross platform with Linux, but as far as I know, LibUsb doesn't support other platforms.

I recommend using the Windows Hid, and USB APIs directly. These are used part of Usb.Net and Hid.Net. If you do need to keep your code cross platform with Linux, you can still use an polymorphism to wrap the LibUsbDotNet library on Linux:

c# program that reading from usb

1 Answers1