// read/write handle to the device
private SafeFileHandle mHandle;

// a pretty .NET stream to read/write from/to
private FileStream mStream;



................................
    }

    // move to the next device
    index++;
}

// 6. clean up our list
HIDImports.SetupDiDestroyDeviceInfoList(hDevInfo);

private void OnReadData(IAsyncResult ar)
{
    // grab the byte buffer
    byte[] buff = (byte[])ar.AsyncState;

    // end the current read
    mStream.EndRead(ar);

    // start reading again
    BeginAsyncRead();
   
    // handle data....
}

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent(); <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<IN HERE??????????????????
        }
    }
}

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load()
        {
            // read/write handle to the device
            private SafeFileHandle mHandle;

            // a pretty .NET stream to read/write from/to
            private FileStream mStream;
            bool found = false;
            Guid guid;
            uint index = 0;

            // 1. get the GUID of the HID class
            HIDImports.HidD_GetHidGuid(out guid);

            // 2. get a handle to all devices that are part of the HID class
            IntPtr hDevInfo = HIDImports.SetupDiGetClassDevs(ref guid, null, IntPtr.Zero, HIDImports.DIGCF_DEVICEINTERFACE);// | HIDImports.DIGCF_PRESENT);

            // create a new interface data struct and initialize its size
            HIDImports.SP_DEVICE_INTERFACE_DATA diData = new HIDImports.SP_DEVICE_INTERFACE_DATA();
            diData.cbSize = Marshal.SizeOf(diData);

            // 3. get a device interface to a single device (enumerate all devices)
            while(HIDImports.SetupDiEnumDeviceInterfaces(hDevInfo, IntPtr.Zero, ref guid, index, ref diData))
            {
                // create a detail struct and set its size
                HIDImports.SP_DEVICE_INTERFACE_DETAIL_DATA diDetail = new HIDImports.SP_DEVICE_INTERFACE_DETAIL_DATA();
                diDetail.cbSize = 5; //should be: (uint)Marshal.SizeOf(diDetail);, but that's the wrong size

                UInt32 size = 0;

                // get the buffer size for this device detail instance (returned in the size parameter)
                HIDImports.SetupDiGetDeviceInterfaceDetail(hDevInfo, ref diData, IntPtr.Zero, 0, out size, IntPtr.Zero);

                // actually get the detail struct
                if(HIDImports.SetupDiGetDeviceInterfaceDetail(hDevInfo, ref diData, ref diDetail, size, out size, IntPtr.Zero))
                {
                    // open a read/write handle to our device using the DevicePath returned
                    mHandle = HIDImports.CreateFile(diDetail.DevicePath, FileAccess.ReadWrite, FileShare.ReadWrite, IntPtr.Zero, FileMode.Open, HIDImports.EFileAttributes.Overlapped, IntPtr.Zero);

                    // 4. create an attributes struct and initialize the size
                    HIDImports.HIDD_ATTRIBUTES attrib = new HIDImports.HIDD_ATTRIBUTES();
                    attrib.Size = Marshal.SizeOf(attrib);

                    // get the attributes of the current device
                    if(HIDImports.HidD_GetAttributes(mHandle.DangerousGetHandle(), ref attrib))
                    {
                        // if the vendor and product IDs match up
                        if(attrib.VendorID == VID && attrib.ProductID == PID)
                        {
                            // 5. create a nice .NET FileStream wrapping the handle above
                            mStream = new FileStream(mHandle, FileAccess.ReadWrite, REPORT_LENGTH, true);
                        }
                        else
                            mHandle.Close();
                    }
                }

                // move to the next device
                index++;
            }

            // 6. clean up our list
            HIDImports.SetupDiDestroyDeviceInfoList(hDevInfo);

            // sure, we could find this out the hard way using HID, but trust me, it's 22
            private const int REPORT_LENGTH = 22;

            // report buffer
            private byte[] mBuff = new byte[REPORT_LENGTH];

            private void BeginAsyncRead()
            {
                // if the stream is valid and ready
                if(mStream.CanRead)
                {
                    // create a read buffer of the report size
                    byte[] buff = new byte[REPORT_LENGTH];

                    // setup the read and the callback
                    mStream.BeginRead(buff, 0, REPORT_LENGTH, new AsyncCallback(OnReadData), buff);
                }
            }

            private void OnReadData(IAsyncResult ar)
            {
                // grab the byte buffer
                byte[] buff = (byte[])ar.AsyncState;

                // end the current read
                mStream.EndRead(ar);

                // start reading again
                BeginAsyncRead();
               
                // handle data....
           }
       }


     }
 }