文件流FileStream案例二

先上代码

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.IO;

namespace 文件流FileStream案例二
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        int TypeW = 0;
        /// <summary>
        /// 选定某个文件夹
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void button1_Click(object sender, EventArgs e)
        {
            FolderBrowserDialog openfolder = new FolderBrowserDialog();
            if (openfolder.ShowDialog() == DialogResult.OK)
            {
                textBox1.Text = Convert.ToString(openfolder.SelectedPath);
                TypeW = 1;
            }
        }

        private void button2_Click(object sender, EventArgs e)
        {
            OpenFileDialog openfile = new OpenFileDialog();
            openfile.Filter = "文本文件|*.txt";
            if (openfile.ShowDialog() == DialogResult.OK)
            {
                FileStream openfilestream = new FileStream(openfile.FileName, FileMode.Open, FileAccess.Read);
                StreamReader sr = new StreamReader(openfilestream, Encoding.Default);
                richTextBox1.Text = sr.ReadToEnd();
                textBox2.Text = Convert.ToString(openfile.FileName);
                sr.Close();
                openfilestream.Close();
                TypeW = 2;
            }
        }

        private void button3_Click(object sender, EventArgs e)
        {
            if (richTextBox1.Text == string.Empty)
            {
                MessageBox.Show("编辑文本文件内容禁止为空", "提示信息");
                return;
            }
            else
            {
                if (TypeW == 1)
                {
                    FileStream fs = new FileStream(textBox1.Text + @"\\anshenwoaini.txt", FileMode.Create, FileAccess.ReadWrite);
                    StreamWriter sw = new StreamWriter(fs, Encoding.Default);
                    sw.Write(richTextBox1.Text);
                    TypeW = 0;
                    MessageBox.Show("已经成功地将文本文件写入");

                    sw.Close();
                    fs.Close();
                }
                else if (TypeW == 2)
                {
                    FileStream fs = new FileStream(textBox2.Text, FileMode.OpenOrCreate, FileAccess.ReadWrite);
                    StreamWriter sw = new StreamWriter(fs, Encoding.Default);
                    sw.Write(richTextBox1.Text);
                    MessageBox.Show("yijingchenggong");
                    sw.Close();
                    fs.Close();
                }
            }
        }
    }
}