C# SharpPcap Cross-thread operation not valid

Hi I'm trying to convert packet capturing in Example3 in SharpPcap new version SharpPcap-2.2.0rc1.src from Console Application to Windows Forms Application.开发者_如何学编程

I'm facing a problem when I tried to add packets has been captured to ListView control I will get an error which is:

(Cross-thread operation not valid: Control 'listViewPackets' accessed from a thread other than the thread it was created on.)

at this line:

listViewPackets.Items.Add(e.Packet.ToString());

any Advice to solve this problem???

here is my code:

using SharpPcap;

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



            // Retrieve the device list

        private void btnLiDevicest_Click(object sender, EventArgs e)
        {
            var devices = LivePcapDeviceList.Instance;
            // If no devices were found print an error
            if (devices.Count < 1)
            {
                MessageBox.Show("No devices were found on this machine");
                return;
            }


            int i = 0;

            // Print out the devices
            foreach (LivePcapDevice dev in devices)
            {

                ///* Description */
                //Console.WriteLine("{0}) {1} {2}", i, dev.Name, dev.Description);
                cmbListDevice.Items.Add(dev.Name + "   " + dev.Description);
                i++;
            }
           LivePcapDevice device = devices[1];
            // Register our handler function to the 'packet arrival' event
            device.OnPacketArrival += new PacketArrivalEventHandler(device_OnPacketArrival);

            // Open the device for capturing
            int readTimeoutMilliseconds = 1000;
            device.Open(DeviceMode.Promiscuous, readTimeoutMilliseconds);
            device.StartCapture();


        }


            //Console.WriteLine();
            //Console.WriteLine("-- Listening on {0}, hit 'Enter' to stop...",
            //    device.Description);
                    /// <summary>
        /// Prints the time and length of each received packet
        /// </summary>
        /// 

        protected  void device_OnPacketArrival(object sender, CaptureEventArgs e)
        {
            DateTime time = e.Packet.PcapHeader.Date;
            uint len = e.Packet.PcapHeader.PacketLength;
            //Console.WriteLine("{0}:{1}:{2},{3} Len={4}", 
            //    time.Hour, time.Minute, time.Second, time.Millisecond, len);

           // Console.WriteLine(e.Packet.ToString());

            listViewPackets.Items.Add(e.Packet.ToString());


        }



        }


}

................................. .................................... here is the original code:

using System;
using System.Collections.Generic;
using SharpPcap;
namespace SharpPcap.Test.Example3
{
    /// <summary>
    /// Basic capture example
    /// </summary>
    public class BasicCap
    {
        public static void Main(string[] args)
        {
            // Print SharpPcap version
            string ver = SharpPcap.Version.VersionString;
            Console.WriteLine("SharpPcap {0}, Example3.BasicCap.cs", ver);

            // Retrieve the device list
            var devices = LivePcapDeviceList.Instance;

            // If no devices were found print an error
            if(devices.Count < 1)
            {
                Console.WriteLine("No devices were found on this machine");
                return;
            }

            Console.WriteLine();
            Console.WriteLine("The following devices are available on this machine:");
            Console.WriteLine("----------------------------------------------------");
            Console.WriteLine();

            int i = 0;

            // Print out the devices
            foreach(LivePcapDevice dev in devices)
            {
                /* Description */
                Console.WriteLine("{0}) {1} {2}", i, dev.Name, dev.Description);
                i++;
            }

            Console.WriteLine();
            Console.Write("-- Please choose a device to capture: ");
            i = int.Parse( Console.ReadLine() );

            LivePcapDevice device = devices[i];

            // Register our handler function to the 'packet arrival' event
            device.OnPacketArrival += 
                new PacketArrivalEventHandler( device_OnPacketArrival );

            // Open the device for capturing
            int readTimeoutMilliseconds = 1000;
            device.Open(DeviceMode.Promiscuous, readTimeoutMilliseconds);

            Console.WriteLine();
            Console.WriteLine("-- Listening on {0}, hit 'Enter' to stop...",
                device.Description);

            // Start the capturing process
            device.StartCapture();

            // Wait for 'Enter' from the user.
            Console.ReadLine();

            // Stop the capturing process
            device.StopCapture();

            Console.WriteLine("-- Capture stopped.");

            // Print out the device statistics
            Console.WriteLine(device.Statistics().ToString());

            // Close the pcap device
            device.Close();
        }

        /// <summary>
        /// Prints the time and length of each received packet
        /// </summary>
        private static void device_OnPacketArrival(object sender, CaptureEventArgs e)
        {
            DateTime time = e.Packet.PcapHeader.Date;
            uint len = e.Packet.PcapHeader.PacketLength;
            Console.WriteLine("{0}:{1}:{2},{3} Len={4}", 
                time.Hour, time.Minute, time.Second, time.Millisecond, len);
            Console.WriteLine(e.Packet.ToString());
        }
    }
}

When making a call to a control from another thread:

if (listView1.InvokeRequired)
{
    listView1.BeginInvoke(new MethodInvoker(
        () => /*whatever you want with listview */));
}
else
{
    /* whatever you want with listview */
}

If you know for sure that it will always be on another thread, then just forget the if/else and use the invoke.

EDIT:

so in your case, it'd look like:

if(listView1.InvokeRequired)
{
    listView1.BeginInvoke(new MethodInvoker(
        () => listViewPackets.Items.Add(e.Packet.ToString()) ));
}
else
{
    listViewPackets.Items.Add(e.Packet.ToString());
}

(again, or just the BeginInvoke call, if it will always run on a different thread)

EDIT 2 You'll notice that Shane uses Invoke and I use BeginInvoke. I use it as a force of habit. Using Invoke will block on the UI thread, and if you're performing an operation that takes longer, using BeginInvoke performs the update to the UI asynchronously.

You need to use Invoke because the packet is coming in on a different thread. UI controls cannot be modified on a thread other than the one they're created on. Invoke will execute the given delegate on the UI thread. For example, you could do this:

this.Invoke(new MethodInvoker(() => listViewPackets.Items.Add(e.Packet.ToString())), null);