C# GPS跟踪系统

我最近正在为我爸爸的公司开发GPS软件。每个卡车司机的电脑里都有一台笔记本电脑，我正试图制作一个软件来定位他们去哪里。从我以前在这里看到的帖子中，有一个人提出了这个建议

System.dll中发生类型为“System.IO.IOException”的未处理异常

其他信息：端口“COM1”不存在。“

这是按钮代码 . `

这是表格的全部代码

`

使用系统；
使用System.Collections.Generic；
使用系统组件模型；
使用系统图；
使用System.IO；
使用System.IO.Ports；
使用系统文本；
使用System.Windows.Forms；
名称空间GPS
{
公共部分类主窗体：窗体
{
私人GGA命令_lastGga；
私人GSA命令_lastGsa；
私人GsvCommand_lastGsv；
私人RMC命令_lastRmc；
私人GLL命令_lastGll；
公共主窗体（）
{
Control.CheckForIllegalCrossThreadCalls=false；
初始化组件（）；
_port.NewLine=“\r\n”；
}
受保护的覆盖无效加载（事件参数e）
{
portList.Items.AddRange（System.IO.Ports.SerialPort.GetPortNames（））；
portList.SelectedIndex=portList.Items.Count-1；
基础荷载（e）；
}
公共卫星[]卫星
{
得到
{
如果（_lastGsv==null）
返回新卫星[0]；
列表卫星=新列表（_lastGsv.Satellites）；
对于（int i=0；iprivate void connectButton_Click (object sender, EventArgs e)
        {
            _port.Open();
            _timer.Start();
        connectButton.Enabled = false;
        disconnectButton.Enabled = true;
        portList.Enabled = false;
    }

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Drawing;
using System.IO;
using System.IO.Ports;
using System.Text;
using System.Windows.Forms;

namespace GPS
{
    public partial class MainForm : Form
    {
        private GgaCommand _lastGga;
        private GsaCommand _lastGsa;
        private GsvCommand _lastGsv;
        private RmcCommand _lastRmc;
        private GllCommand _lastGll;
    public MainForm ()
    {
        Control.CheckForIllegalCrossThreadCalls = false;

        InitializeComponent();

        _port.NewLine = "\r\n";
    }

    protected override void OnLoad (EventArgs e)
    {
        portList.Items.AddRange(System.IO.Ports.SerialPort.GetPortNames());
        portList.SelectedIndex = portList.Items.Count - 1;

        base.OnLoad(e);
    }

    public Satellite[] Satellites
    {
        get
        {
            if (_lastGsv == null)
                return new Satellite[0];

            List<Satellite> sats = new List<Satellite>(_lastGsv.Satellites);

            for (int i = 0; i < sats.Count; i++)
                sats[i] = sats[i] + _lastGsa;

            return sats.ToArray();
        }
    }

    private void portList_SelectedIndexChanged (object sender, EventArgs e)
    {
        _port.PortName = portList.SelectedItem as string;
    }

    private void connectButton_Click (object sender, EventArgs e)
    {
        _port.Open();
        _timer.Start();

        connectButton.Enabled = false;
        disconnectButton.Enabled = true;
        portList.Enabled = false;
    }

    private void disconnectButton_Click (object sender, EventArgs e)
    {
        _timer.Stop();
        _port.Close();

        connectButton.Enabled = true;
        disconnectButton.Enabled = false;
        portList.Enabled = true;
    }

    private void timer_Tick (object sender, EventArgs e)
    {
        try {
            string data = _port.ReadLine();

            if (String.IsNullOrEmpty(data) == false) {
                ProcessCommand(data);
            }
        } catch (Exception exc) {
            System.Diagnostics.Debug.WriteLine(exc);
        }
    }

    private void altitude_CheckedChanged (object sender, EventArgs e)
    {
        RefreshAltitude();
    }

    private void distance_CheckedChanged (object sender, EventArgs e)
    {
        RefreshDistance();
    }

    private void ProcessCommand (string data)
    {
        // all commands start with dollar signs
        if (data[0] != '$')
            return;

        //System.Diagnostics.Debug.WriteLine(data, "Command");

        if (data.IndexOf('*') != -1)
            data = data.Substring(0, data.IndexOf('*'));

        switch (data.Substring(3, 3)) {

            case "GGA":
                _lastGga = new GgaCommand(data);
                latitudeValueLabel.Text = _lastGga.Location.Latitude.ToString("N6");
                longitudeValueLabel.Text = _lastGga.Location.Longitude.ToString("N6");
                RefreshAltitude();
                break;

            case "GSA":
                _lastGsa = new GsaCommand(data);
                RefreshSattellites();
                break;

            case "GSV":
                _lastGsv = _lastGsv + new GsvCommand(data);
                RefreshSattellites();
                break;

            case "RMC":
                _lastRmc = new RmcCommand(data);
                directionImage.Invalidate();
                bearingValueLabel.Text = _lastRmc.DirectionalAngleInDegrees.ToString();
                RefreshDistance();
                break;

            case "GLL":
                _lastGll = new GllCommand(data);
                break;

            default:
                System.Diagnostics.Trace.WriteLine("*** " + data.Substring(3, 3) + " Not Handled", "Command");
                break;
        }
    }

    private void RefreshAltitude ()
    {
        float altitude = _lastGga.Location.AltitudeInFeet;

        if (altitudeInMetersRadio.Checked)
            altitude = _lastGga.Location.AltitudeInMeters;

        altitudeValueLabel.Text = altitude.ToString();
    }

    private void RefreshDistance ()
    {
        float speed = _lastRmc.Knots;

        if (milesPerHourRadio.Checked)
            speed = _lastRmc.MilesPerHour;
        else if (kilometersPerHourRadio.Checked)
            speed = _lastRmc.KilometersPerHour;

        speedLabel.Text = speed.ToString("N2");
    }

    private void RefreshSattellites ()
    {
        Satellite[] satellites = this.Satellites;

        for (int i = 0; i < satellites.Length; i++) {
            Satellite sat = satellites[i];
            ListViewItem item = sat.Tag as ListViewItem;

            if (item == null) {
                item = new ListViewItem(new string[] {
                        sat.Prn.ToString(),
                        sat.SignalQuality.ToString()
                    },
                    satelliteList.Groups[sat.HasFix ? "hasFixGroup" : "doesNotHaveFixGroup"]
                );

                satelliteList.Items.Add(item);
            }

            sat.Tag = item;
        }

        satilliteLocationImage.Invalidate();
    }

    private void satilliteLocationImage_Paint (object sender, PaintEventArgs e)
    {
        float centerXF = (float)satilliteLocationImage.Bounds.Width / 2F;
        int centerX = satilliteLocationImage.Bounds.Width / 2;
        float centerYF = (float)satilliteLocationImage.Bounds.Height / 2F;
        int centerY = satilliteLocationImage.Bounds.Height / 2;
        float maxRadius = (Math.Min((float)satilliteLocationImage.Bounds.Height, (float)satilliteLocationImage.Bounds.Width) - 20F) / 2F;

        using (Pen circlePen = new Pen(Color.DarkBlue, 1)) {

            double[] elevations = new double[] { 0, Math.PI / 2, Math.PI / 3, Math.PI / 6 };

            foreach (double elevation in elevations) {
                float radius = Convert.ToSingle(System.Math.Cos(elevation) * maxRadius);
                e.Graphics.DrawEllipse(circlePen, (centerXF - radius), (centerYF - radius), (2F * radius), (2F * radius));
            }

            e.Graphics.DrawLine(circlePen, new Point(centerX - 4, centerY), new Point(centerX + 4, centerY));
            e.Graphics.DrawLine(circlePen, new Point(centerX, centerY - 4), new Point(centerX, centerY + 4));
        }

        if (_lastGsv == null)
            return;

        Satellite[] satellites = this.Satellites;

        if (satellites != null && satellites.Length > 0) {

            using (Pen satellitePen = new Pen(Color.Yellow, 4F)) {
                using (Pen hasFixSatellitePen = new Pen(Color.Green, 4F)) {

                    foreach (Satellite sat in satellites) {
                        double h = (double)System.Math.Cos((sat.Elevation * Math.PI) / 180D) * maxRadius;

                        float satX = centerXF + Convert.ToSingle(h * Math.Sin(((float)sat.Azimuth * Math.PI) / 180D));
                        float satY = centerYF - Convert.ToSingle(h * Math.Cos(((float)sat.Azimuth * Math.PI) / 180D));

                        e.Graphics.DrawRectangle(sat.HasFix ? hasFixSatellitePen : satellitePen, satX, satY, 4F, 4F);
                        e.Graphics.DrawString(sat.Prn.ToString(), new Font("Tahoma", 8, FontStyle.Regular), new System.Drawing.SolidBrush(Color.Black), new PointF(satX + 5F, satY + 5F));
                    }
                }
            }
        }
    }

    private void directionImage_Paint (object sender, PaintEventArgs e)
    {
        int centerX = directionImage.Bounds.Width / 2;
        int centerY = directionImage.Bounds.Height / 2;
        float maxWidth = Math.Min((float)directionImage.Bounds.Height, (float)directionImage.Bounds.Width) - 40F;
        float centerXF = (float)directionImage.Bounds.Width / 2F;
        float centerYF = (float)directionImage.Bounds.Height / 2F;
        float radius = maxWidth / 2F;

        e.Graphics.DrawLine(Pens.Black, new Point(0, centerY), new Point(directionImage.Bounds.Width, centerY));
        e.Graphics.DrawLine(Pens.Black, new Point(centerX, 0), new Point(centerX, directionImage.Bounds.Height));
        e.Graphics.DrawEllipse(Pens.Black, centerXF - (maxWidth / 2F), centerYF - (maxWidth / 2F), maxWidth, maxWidth);

        using (Font directionFont = new Font("Tahoma", 12F, FontStyle.Bold)) {
            e.Graphics.DrawString("N", directionFont, Brushes.Purple, centerXF, 0F);
            e.Graphics.DrawString("S", directionFont, Brushes.Purple, centerXF, directionImage.Bounds.Height - 20);
            e.Graphics.DrawString("E", directionFont, Brushes.Purple, directionImage.Bounds.Width - 20, centerYF);
            e.Graphics.DrawString("W", directionFont, Brushes.Purple, 0, centerYF);
        }

        using (Pen anglePen = new Pen(Color.Blue, 4F)) {
            e.Graphics.DrawLine(anglePen, new PointF(centerX, centerY), new PointF((radius * Convert.ToSingle(Math.Cos(_lastRmc.DirectionalAngleInRadians))) + centerXF, (radius * Convert.ToSingle(Math.Sin(_lastRmc.DirectionalAngleInRadians))) + centerYF));
        }
    }
}