Getting client information in C#

Question

I have an application that scans the local network for connected PC's.

I want to get the client information (IP address, MAC address, Host name...) and the connection state (download rate, upload rate), and put them in the ListView, but the problem is that this information is not constant!

How could I get this information in real time? The info in the ListView changes every time the info of the client changes?

My current code:

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


namespace WindowsFormsApplication5
{


public partial class Form1 : Form
{
    private IPScanner _scanner;

    private class HostSorterByIP : IComparer
    {
        public int Compare(object x, object y)
        {
            byte[] bytes1 = ((IPScanHostState)((ListViewItem)x).Tag).Address.GetAddressBytes();
            byte[] bytes2 = ((IPScanHostState)((ListViewItem)y).Tag).Address.GetAddressBytes();

            int i = bytes1.Length - 1;
            for (; i > 0 && bytes1[i] == bytes2[i]; i--)
                ;

            return bytes1[i] - bytes2[i];
        }
    }

    public Form1()
    {
        InitializeComponent();

        _scanner = new IPScanner((int)_spnConcurrentPings.Value, (int)_spnPingsPerScan.Value, _cbContinuousScan.Checked,
            (int)_spnTimeout.Value, (int)_spnTTL.Value, _cbDontFragment.Checked, (int)_spnBufferSize.Value);

        _scanner.OnAliveHostFound += new IPScanner.AliveHostFoundDelegate(_scanner_OnAliveHostFound);

        _scanner.OnStartScan += new IPScanner.ScanStateChangeDelegate(_scanner_OnStartScan);
        _scanner.OnStopScan += new IPScanner.ScanStateChangeDelegate(_scanner_OnStopScan);
        _scanner.OnRestartScan +=new IPScanner.ScanStateChangeDelegate(_scanner_OnRestartScan);
        _scanner.OnScanProgressUpdate +=new IPScanner.ScanProgressUpdateDelegate(_scanner_OnScanProgressUpdate);

        _lvAliveHosts.ListViewItemSorter = new HostSorterByIP();

        _cmbRangeType.SelectedIndex = 0;
    }

    private void _scanner_OnAliveHostFound(IPScanner scanner, IPScanHostState host)
    {
        if (InvokeRequired)
        {
            BeginInvoke(new IPScanner.AliveHostFoundDelegate(_scanner_OnAliveHostFound), scanner, host);
            return;
        }

        ListViewItem item = new ListViewItem();
        item.Tag = host;

        item.BackColor = Color.GreenYellow;
        item.SubItems.Add(host.Address.ToString());
        item.SubItems.Add("");
        item.SubItems.Add("");
        item.SubItems.Add("");

        _lvAliveHosts.Items.Add(item);
        _lvAliveHosts.Sort();

        host.OnHostNameAvailable += new IPScanHostState.HostNameAvailableDelegate(host_OnHostNameAvailable);
        host.OnStateChange += new IPScanHostState.StateChangeDelegate(host_OnStateChange);

        if (!host.IsTesting())
        {
            item.ImageIndex = (int)host.QualityCategory;
            item.SubItems[2].Text = host.AvgResponseTime.ToString("F02") + " ms";
            item.SubItems[3].Text = ((float)(host.LossCount) / host.PingsCount).ToString("P");
            item.SubItems[4].Text = host.HostName;
        }

        //AddLogEntry("Host [" + host.Address.ToString() + "] is alive.");

        Timer newTimer = new Timer();
        newTimer.Tag = item;
        newTimer.Interval = 2000;
        newTimer.Tick += new EventHandler(newTimer_Tick);

        newTimer.Enabled = true;
    }

    void host_OnHostNameAvailable(IPScanHostState host)
    {
        if (InvokeRequired)
        {
            BeginInvoke(new IPScanHostState.HostNameAvailableDelegate(host_OnHostNameAvailable), host);
            return;
        }

        ListViewItem item = FindListViewItem(host);
        if (item != null)
            item.SubItems[4].Text = host.HostName;
    }

    private ListViewItem FindListViewItem(IPScanHostState host)
    {
        foreach (ListViewItem item in _lvAliveHosts.Items)
        {
            if (item.Tag == host)
                return item;
        }

        return null;
    }

    private void host_OnStateChange(IPScanHostState host, IPScanHostState.State oldState)
    {
        if (InvokeRequired)
        {
            BeginInvoke(new IPScanHostState.StateChangeDelegate(host_OnStateChange), host, oldState);
            return;
        }

        if (!host.IsTesting())
        {
            ListViewItem item = FindListViewItem(host);
            if (item != null)
            {
                if (host.IsAlive())
                {
                    item.ImageIndex = (int)host.QualityCategory;
                    item.SubItems[2].Text = host.AvgResponseTime.ToString("F02") + " ms";
                    item.SubItems[3].Text = ((float)(host.LossCount) / host.PingsCount).ToString("P");
                }
                else
                {
                    //AddLogEntry("Host [" + host.Address.ToString() + "] died.");

                    host.OnStateChange -= host_OnStateChange;
                    host.OnHostNameAvailable -= host_OnHostNameAvailable;

                    item.BackColor = Color.IndianRed;

                    Timer removeTimer = new Timer();
                    removeTimer.Tag = item;
                    removeTimer.Interval = 2000;
                    removeTimer.Tick += new EventHandler(removeTimer_Tick);

                    removeTimer.Enabled = true;
                }
            }
        }
    }

    void newTimer_Tick(object sender, EventArgs e)
    {
        Timer timer = (Timer)sender;

        timer.Stop();
        timer.Tick -= newTimer_Tick;

        ListViewItem item = (ListViewItem)timer.Tag;
        item.BackColor = Color.White;
    }

    void removeTimer_Tick(object sender, EventArgs e)
    {
        Timer timer = (Timer)sender;

        timer.Stop();
        timer.Tick -= newTimer_Tick;

        ListViewItem item = (ListViewItem)timer.Tag;
        _lvAliveHosts.Items.Remove(item);
    }

    private void _scanner_OnStartScan(IPScanner scanner)
    {
        if (InvokeRequired)
        {
            BeginInvoke(new IPScanner.ScanStateChangeDelegate(_scanner_OnStartScan), scanner);
            return;
        }

        foreach (ListViewItem item in _lvAliveHosts.Items)
        {
            ((IPScanHostState)item.Tag).OnStateChange -= host_OnStateChange;
            ((IPScanHostState)item.Tag).OnHostNameAvailable -= host_OnHostNameAvailable;
        }

        _lvAliveHosts.Items.Clear();

        _prgScanProgress.Value = 0;

        EnableSettings(false);
    }

    private void EnableSettings(bool enable)
    {
        _cmbRangeType.Enabled = _tbRangeStart.Enabled = _tbRangeEnd.Enabled = _spnTimeout.Enabled = _spnTTL.Enabled = _spnBufferSize.Enabled = _cbDontFragment.Enabled =
            _spnConcurrentPings.Enabled = _spnPingsPerScan.Enabled = _cbContinuousScan.Enabled = enable;

        _btnStartStop.Text = enable ? "&Start" : "&Stop";
        if (enable)
            _prgScanProgress.Text = "Scanner is not running!";
    }

    private void _btnStartStop_Click(object sender, EventArgs e)
    {
        if (!_scanner.Active)
        {
            try
            {
                _scanner.Start(_cmbRangeType.SelectedIndex == 0
                    ? new IPScanRange(IPAddress.Parse(_tbRangeStart.Text), IPAddress.Parse(_tbRangeEnd.Text))
                    : new IPScanRange(IPAddress.Parse(_tbRangeStart.Text), int.Parse(_tbRangeEnd.Text)));
            }
            catch (FormatException)
            {
                MessageBox.Show(this, "Cannot parse IP range or subnetmask!", "Error!", MessageBoxButtons.OK, MessageBoxIcon.Error);
            }
        }
        else
            _scanner.Stop(false);
    }

    private void _scanner_OnStopScan(IPScanner scanner)
    {
        if (InvokeRequired)
        {
            BeginInvoke(new IPScanner.ScanStateChangeDelegate(_scanner_OnStopScan), scanner);
            return;
        }

        EnableSettings(true);


        _prgScanProgress.Value = 0;
    }

    void _scanner_OnRestartScan(IPScanner scanner)
    {
        if (InvokeRequired)
        {
            BeginInvoke(new IPScanner.ScanStateChangeDelegate(_scanner_OnRestartScan), scanner);
            return;
        }


        _prgScanProgress.Value = 0;
    }

    void _scanner_OnScanProgressUpdate(IPScanner scanner, IPAddress currentAddress, ulong progress, ulong total)
    {
        if (InvokeRequired)
        {
            BeginInvoke(new IPScanner.ScanProgressUpdateDelegate(_scanner_OnScanProgressUpdate), scanner, currentAddress, progress, total);
            return;
        }

        int prog = (int)((100 * progress) / total);
        _prgScanProgress.Value = prog;
        _prgScanProgress.Text = prog.ToString() + "%" + " [" + currentAddress.ToString() + "]";
    }

    private void _cmbRangeType_SelectedIndexChanged(object sender, EventArgs e)
    {
        if (_cmbRangeType.SelectedIndex == 0)
        {
            _lRangeSep.Text = "-";
            _lRangeEnd.Text = "Range &End:";
            _tbRangeEnd.Size = new Size(130, _tbRangeEnd.Size.Height);
        }
        else
        {
            _lRangeSep.Text = "/";
            _lRangeEnd.Text = "Subnet &Mask:";
            _tbRangeEnd.Size = new Size(32, _tbRangeEnd.Size.Height);
        }
    }

    //private void _lvAliveHosts_DoubleClick(object sender, EventArgs e) { _btnAddHost_Click(sender, e); }

    private void IPScanForm_FormClosing(object sender, FormClosingEventArgs e) { _scanner.Stop(true); }

    private ListViewItem.ListViewSubItem _activeTooltipSubitem = null;

    private static string[] QualityCategoryNames = { "Very Poor", "Poor", "Fair", "Good", "Very Good", "Excellent", "Perfect" };

    private void _lvAliveHosts_MouseMove(object sender, MouseEventArgs e)
    {
        ListViewItem item = _lvAliveHosts.HitTest(e.Location).Item;
        if (item != null)
        {
            ListViewItem.ListViewSubItem subitem = _lvAliveHosts.HitTest(e.Location).SubItem;
            if (subitem != null && item.SubItems.IndexOf(subitem) == 0)
            {
                if (_activeTooltipSubitem != subitem)
                {
                    _ttQuality.Show("Quality: " + QualityCategoryNames[item.ImageIndex], _lvAliveHosts, item.SubItems[1].Bounds.X, subitem.Bounds.Y);
                    _activeTooltipSubitem = subitem;
                }

                return;
            }
        }

        _activeTooltipSubitem = null;
        _ttQuality.Hide(_lvAliveHosts);
    }


}
}

Answer 1

I would create the list of clients and show them in the listview.

Than, in a background thread, every X seconds, poll all of the current clients. Next , compare the list of updated clients to a list of clients from last update.

What remain to do is to add any new client to the list, and remove any client which no longer exists.

Pay attention to the context, use InvokeRequired() to get access to the UI control from the background thread.

EDIT:

here is how to run a background thread:

static void Main(string[] args)
        {

            Thread worker = new Thread(DoBackgroundWork);
        }

        public static void DoBackgroundWork()
        {


            while (true)
            {
                //Sleep 10 seconds
                Thread.Sleep(10000);

                //Do some work and than post to the control using Invoke()

            }

        }