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, , data.Length);
                     fs.Close();
                     fs.Dispose();
                 }
             }
         }
     }
 }