C#文件流读写文件的简单winform实现

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

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

        private void btnOpen_Click(object sender, EventArgs e)
        {
            using (OpenFileDialog ofd = new OpenFileDialog())
            {
                if (ofd.ShowDialog() != System.Windows.Forms.DialogResult.OK)
                {
                    return;
                }

            using (FileStream fs = new FileStream(ofd.FileName, FileMode.Open, FileAccess.Read))
                {
                    using (StreamReader sr = new StreamReader(fs,Encoding.Default))
                    {
                        while (!sr.EndOfStream)
                        {
                            string line = sr.ReadLine();
                            this.txtContent.Text += line;
                        }
                        sr.Close();
                    }
                    fs.Close();
                    fs.Dispose();
                }
            }
        }

        private void btnSave_Click(object sender, EventArgs e)
        {
            using (SaveFileDialog sfd = new SaveFileDialog())
            {   
                   sfd.DefaultExt = "txt";
                   sfd.Filter = "文本文件(*.txt)|*.txt|所有文件(*.*)|*.*";
                if (sfd.ShowDialog() != System.Windows.Forms.DialogResult.OK)
                {
                    return;
                }
                using (FileStream fs = new FileStream(sfd.FileName, FileMode.OpenOrCreate, FileAccess.Write))
                {
                    string txt = txtContent.Text.Replace("\n","\r\n");
                    byte[] data = Encoding.UTF8.GetBytes(txt);
                    fs.Write(data, 0, data.Length);
                    fs.Close();
                    fs.Dispose();
                }
            }
        }
    }
}