C#第十周任务之最后一项之创建一个如下的窗体，并在窗体上放置一个菜单、一个工具栏控件。菜单内容如第二个图所示。工具栏上有两个按钮，分别对应“打开文本文件”、“保存文本文件”。菜单和工具栏具体功能实现可

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;

using System.IO;
using System.Windows.Forms;

namespace WindowsFormsApplication9
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void toolStripComboBox1_Click(object sender, EventArgs e)
        {

        }

        private void toolStripButton1_Click(object sender, EventArgs e)
        {
            this.saveFileDialog1.Filter = "*.txt|*.txt";  
            this.saveFileDialog1.ShowDialog();  
           string file = this.saveFileDialog1.FileName;  
            if (string.IsNullOrEmpty(file)) return;  
            //以下为写字符到文本文件，需要添加System.IO引用   
            //创建一个文件流   
            FileStream fs = new FileStream(file, FileMode.OpenOrCreate,  
                FileAccess.Write);  
           //创建一个StreamWriter对象   
           StreamWriter sw = new StreamWriter(fs);  
            sw.Write(this.textBox1.Text);              //释放StreamWriter对象,文件流对象   
           sw.Dispose();  
            fs.Dispose();  

        }

        private void toolStripButton2_Click(object sender, EventArgs e)
        {
            this.openFileDialog1.Filter = "*.txt|*.txt";
            this.openFileDialog1.ShowDialog();
            string file = this.openFileDialog1.FileName;
            if (string.IsNullOrEmpty(file)) return;

            //以下为写字符到文本文件，需要添加System.IO引用
            //创建一个文件流
            FileStream fs = new FileStream(file, FileMode.Open,
                FileAccess.Read);
            //创建一个StreamWriter对象
            StreamReader sr = new StreamReader(fs);
            this.textBox1.Text = sr.ReadToEnd();
            //释放StreamWriter对象,文件流对象
            sr.Dispose();
            fs.Dispose();

        }

        private void textBox1_TextChanged(object sender, EventArgs e)
        {

        }
    }
}