winfrom ListBox 使用 點擊彈窗

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 ToUpdateGasStationMis.練習
{
    public partial class FrmDemo : Form
    {
        public FrmDemo()
        {
            InitializeComponent();
        }
        /// <summary>
        /// 顯示listBox
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void button1_Click(object sender, EventArgs e)
        {
            this.listBox1.Items.Clear();
            this.listBox1.Items.Add("軟件部");
            this.listBox1.Items.Add("測試部");
            this.listBox1.Items.Add("採購部");
            this.listBox1.Items.Add("銷售部");
            this.listBox1.Items.Add("人事部");

        }
        /// <summary>
        /// 添加ListBox
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void button2_Click(object sender, EventArgs e)
        {
            try
            {
                listBox1.Items.Insert(2, "插入值");
                label1.Text = "已添加" + listBox1.Items.Count.ToString() + "記錄條數";
            }
            catch (Exception ex )
            {

            }
            
        }
        /// <summary>
        /// ListBox 點擊彈窗
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void listBox1_SelectedIndexChanged(object sender, EventArgs e)
        {
            MessageBox.Show("您選擇的部門是："+listBox1.SelectedItem.ToString()+"位列第"+listBox1.SelectedIndex.ToString(),"信息提示！");
        }
        /// <summary>
        /// 打開加載    
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void FrmDemo_Load(object sender, EventArgs e)
        {
            this.comboBox1.Items.Add("a1");
            this.comboBox1.Items.Add("a2");
            this.comboBox1.Items.Add("a3");
            this.comboBox1.Items.Add("a4");
            this.comboBox1.Items.Add("a5");
            this.comboBox1.Items.Add("a6");
            this.comboBox1.Items.Add("a7");

        }
    }
}