C#列表框通过单击项目填充文本框

我的listbox有一些问题，我一直在尝试制作它，这样当我点击一个项目时，它会用该项目的信息填充文本框（如下图所示）。https://i.stack.imgur.com/G32uq.jpg（不会让我发布图片）。

这是我的代码（我目前拥有的代码将用我需要的内容填充文本框，但我希望它能够通过单击项目来完成同样的操作）。

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;
using System.IO;
namespace WindowsFormsApplication1
        {
        public partial class Form1 : Form
        {
    private int index;
    private const int SIZE = 4;
    private int count = 0;
    private Employee[] employees = new Employee[SIZE];
    List<Employee> listEmp = new List<Employee>(SIZE);
    public Form1()
    {
        InitializeComponent();
        listEmp.Add(new Hourly(1, "Karl", "lane drive", "201-9090", 40, 12.00)); //item1
        listEmp.Add(new Salaried(2, "Steve", "circle road", "803-1230", 1200)); // item2
        listEmp.Add(new Hourly(3, "Westley", "square alley", "892-2000", 40, 10.00)); //item3
        listEmp.Add(new Salaried(4, "Anders", "triangle boulevard", "910-8765", 1000)); //item4
        index = 0;
        computPayBtn.Enabled = true;
        listBox1.DataSource = listEmp;
    }
    // opens a file and reads data into the employee objects
    private void openToolStripMenuItem1_Click(object sender, EventArgs e)
    {
        Stream myStream = null;
        Employee tempEmploy = null;
        string type = null;
        OpenFileDialog openFileDialog1 = new OpenFileDialog();
        openFileDialog1.InitialDirectory = "c:''";
        openFileDialog1.Filter = "text files (*.txt)|*txt";
        count = 0;
        if (openFileDialog1.ShowDialog() == DialogResult.OK)
        {
            if ((myStream = openFileDialog1.OpenFile()) != null)
            {
                StreamReader data = new StreamReader(myStream);
                do
                {
                    type = data.ReadLine();
                    if (type != null)
                    {
                        if (type == "hourly")
                            tempEmploy = new Hourly();
                        else if (type == "salaried")
                            tempEmploy = new Salaried();
                        tempEmploy.ReadData(data);
                        employees[count++] = tempEmploy;
                    }
                } while (type != null);
                computPayBtn.Enabled = true;
                count = 0;
            }
        }
    }
    private void exitToolStripMenuItem1_Click(object sender, EventArgs e)
    {
        this.Close();
    } 
    // shows next employee when clicked.     
    private void computPayBtn_Click_1(object sender, EventArgs e)
    {
        checkbox.Clear( );
        int index = count;
        if (index < SIZE)
        {
            string emp = "Fluffshuffle Electronics                     check no. ";
            emp += string.Format("{0}", index);
            emp += Environment.NewLine;
            emp += Environment.NewLine;
            emp += "          Pay to the order of ";
            emp += employees[index].Name;
            emp += Environment.NewLine;
            emp += "          ";
            emp += string.Format("{0:C}", employees[index].CalcPay());
            emp += Environment.NewLine;
            emp += Environment.NewLine;
            emp += "                       First National Bank";
            checkbox.Text = emp;
            namebox.Text = employees[index].Name;
            addressbox.Text = employees[index].Address;
            phonebox.Text = employees[index].PhoneNum;
            empNumbox.Text = string.Format("{0}", employees[index].EmpNum);
            Hourly houremploy = employees[index] as Hourly;
            if (houremploy != null)
            {
                hoursbox.Text = string.Format("{0:F2}", houremploy.HoursWorked);
                wagebox.Text = string.Format("{0:F2}", houremploy.HourlyWage);
                salarybox.Clear();
            }
            Salaried salemploy = employees[index] as Salaried;
            if (salemploy != null)
            {
                hoursbox.Clear();
                wagebox.Clear();
                salarybox.Text = string.Format("{0:F2}", salemploy.Salary);
            }
            count++;
        } 
        else
        {
            computPayBtn.Enabled = false;
            namebox.Clear( );
            addressbox.Clear(); ;
            phonebox.Clear(); ;
            empNumbox.Clear( );
            hoursbox.Clear();
            wagebox.Clear();
            salarybox.Clear();
            count = 0;
        }
    }
    // saves employee objects into a txt file.
    private void saveToolStripMenuItem_Click(object sender, EventArgs e)
    {
        Stream myStream = null;
        count = SIZE;
        SaveFileDialog saveFileDialog = new SaveFileDialog();
        saveFileDialog.InitialDirectory = "c:''";
        saveFileDialog.Filter = "text files (*.txt)|*txt";
        if (saveFileDialog.ShowDialog() == DialogResult.OK)
        {
            if ((myStream = saveFileDialog.OpenFile()) != null)
            {
                StreamWriter data = new StreamWriter(myStream);
                for (int i = 0; i < count; i++)
                {
                    employees[i].WriteData(data);
                    employees[i] = null; 
                }
                data.Close();
                computPayBtn.Enabled = false;
                count = 0;
            }
        }
    }
    private void Form1_Load(object sender, EventArgs e)
    {
    }
    private void listBox1_SelectedIndexChanged(object sender, EventArgs e)
    {
    }
    }
}

和类

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;
namespace WindowsFormsApplication1
{
    // provides methods to read and write objects to a file
    public interface IStorable
    {
        // writes object's data to a StreamWriter object
        // The StreamReader object to write to
        void WriteData(StreamWriter swo);
        // reads object's data from a StreamReader object
        // The StreamReader object to read from
        void ReadData(StreamReader sro);
    }
    public abstract class Employee : IStorable
    {
        private int empNum;
        private string name;
        private string address;
        private string phoneNum;
        protected const double STATE_TAX = 0.075;
        protected const double FED_TAX = 0.20;
        // set data members to defaults
        public Employee()
        {
            empNum = 0;
            name = "unknown";
            address = "unknown";
            phoneNum = "unknown";
        }
        //  set data members to values passed to method
        //  employee number, name, address, and phone number
        public Employee(int _empNum, string _name, string _address, string _phoneNum)
        {
            empNum = _empNum;
            name = _name;
            address = _address;
            phoneNum = _phoneNum;
        }
        public int EmpNum
        {
            get { return empNum; }
            set { empNum = value; }
        }
        public string Name
        {
            get { return name; }
            set { name = value; }
        }
        public string Address
        {
            get { return address; }
            set { address = value; }
        }
        public string PhoneNum
        {
            get { return phoneNum; }
            set { phoneNum = value; }
        }
        // reads object's data from a StreamReader object
        // The method is virtual so we can use polymorphism
        public virtual void ReadData(StreamReader sro)
        {
            EmpNum = int.Parse(sro.ReadLine());
            Name = sro.ReadLine();
            Address = sro.ReadLine();
            PhoneNum = sro.ReadLine();
        }
        // writes object's data to a StreamReader object
        // The method is virtual so we can use polymorphism
        public virtual void WriteData(StreamWriter sro)
        {
            sro.WriteLine(this.EmpNum);
            sro.WriteLine(this.Name);
            sro.WriteLine(this.Address);
            sro.WriteLine(this.PhoneNum);
        }
        // calculates the employee's net pay
        public abstract double CalcPay();
    } 
    // The Hourly Class - represents an hourly employee
    // Inherits from Employee
    class Hourly : Employee
    {
        private const int WEEK = 40;
        private const double BONUS = 1.5;
        private double hoursWorked;
        private double hourlyWage;
        //set data members to defaults
        public Hourly()
        {
            hoursWorked = 0.0;
            hourlyWage = 0.0;
        }
        // set data members to values passed as arguments
        // employee number, name, address, phone number, hours, and wage
        public Hourly(int _empNum, string _name, string _address, string _phoneNum, double _hours, double _wage)
            : base(_empNum, _name, _address, _phoneNum)
        {
            hoursWorked = _hours;
            hourlyWage = _wage;
        }
        public double HoursWorked
        {
            get { return hoursWorked; }
            set { hoursWorked = value; }
        }
        public double HourlyWage
        {
            get { return hourlyWage; }
            set { hourlyWage = value; }
        }
        //  calculates gross pay
        //  hours * wage + time and 1/2 for overtime
        public override double CalcPay()
        {
            double overTime = 0.0;
            if (hoursWorked > WEEK)
            {
                overTime = hoursWorked - WEEK;
                hoursWorked -= WEEK;
            }
            double grossPay = hoursWorked * hourlyWage + overTime * hourlyWage * BONUS;
            double stateTax = grossPay * STATE_TAX;
            double fedTax = grossPay * FED_TAX;
            return (grossPay - stateTax - fedTax);
        }
        // reads object's data from a StreamReader object
        // Over-rides the ReadData method in Employee
        public override void ReadData(StreamReader sro)
        {       
            HoursWorked = double.Parse(sro.ReadLine());
            HourlyWage = double.Parse(sro.ReadLine());
            base.ReadData(sro);
        }
        // writes object's data to a StreamWriter object
        // Over-rides the WriteData method in Employee
        public override void WriteData(StreamWriter swo)
        {
            swo.WriteLine("hourly");
            swo.WriteLine(this.HoursWorked);
            swo.WriteLine(this.HourlyWage);
            base.WriteData(swo);
        }
    }
    class Salaried : Employee
    {
        private const double BENEFITS = 0.0524;
        private double salary;
        // set data members to defaults
        public Salaried()
        {
            salary = 0.0;
        }
        // set data members to values passed as arguments
        // employee number, name, address, phone number, salary
        public Salaried(int _empNum, string _name, string _address, string _phoneNum, double _salary)
            : base(_empNum, _name, _address, _phoneNum) 
        {
            salary = _salary;
        }
        public double Salary
        {
            get { return salary; }
            set { salary = value; }
        }
        // calculates pay for a salaried employee
        public override double CalcPay()
        {
            double stateTax = salary * STATE_TAX;
            double fedTax = salary * FED_TAX;
            double bennies = salary * BENEFITS;
            return (salary - stateTax - fedTax - bennies);
        }
        //reads object's data from a StreamReader object
        public override void ReadData(StreamReader sro)
        {
            Salary = double.Parse(sro.ReadLine());
            base.ReadData(sro);  // call Employee's ReadData to get name, address, etc
        }
        // writes data to StreamWriter 
        public override void WriteData(StreamWriter swo)
        {
            swo.WriteLine("salaried");
            swo.WriteLine(this.Salary);
            base.WriteData(swo); 
        }
    }
}

提前感谢您的帮助。

private void listBox1_Clik(object sender, EventArgs e)
{
  Employee employee = listBox1.SelectedItems[0] as Employee;
  if (employee != null)
  {
      // use the employee object to populate the textbox.
  }
}