C#下动态更新combobox的下拉表单

                          

加载一个文件 然后每次打开读取文件，每次选中或者添加新的combobox选项，向文件进行写入
以下代码测试过 所用控件为combobox和button
using System;
using System.Text;
using System.IO;
using System.Windows.Forms;

namespace _1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
        string path = null;
        private void Form1_Load(object sender, EventArgs e)
        {
             path= @"d:\1.ini";
            if (File.Exists(path))
            {
                //读取配置文件，并加载到combobox选项中，默认选中第一个选项
                StreamReader sr = new StreamReader(path,Encoding.Default);
                while (sr.Peek() > 0)
                {
                    comboBox1.Items.Add(sr.ReadLine());
                }
                sr.Close();
                //选中combobox第一个
                comboBox1.Text=(string)comboBox1.Items[0];
            }
        }

        private void button1_Click(object sender, EventArgs e)
        {      
            //添加或者选择combobox选项后，更新combobox选项顺序
            if (comboBox1.Items.Contains(comboBox1.Text))
            {
                comboBox1.Items.Remove(comboBox1.Text);
            }
            comboBox1.Items.Insert(0, comboBox1.Text);
            //保存combobox的选项内容到配置文件1.ini
            StreamWriter sw = new StreamWriter(path);
            for (int i = 0; i < comboBox1.Items.Count; i++)
            {
                sw.WriteLine(comboBox1.Items[i]);
            }
            sw.Close();
        }
    }
}