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 txt
{
  public partial class Form1 : Form
  {
    // string path;
    public Form1()
    {
      InitializeComponent();
      button3.Click+=button3_Click;
    }
 
    private void textBox2_TextChanged(object sender, EventArgs e)
    {
      string path1 = textBox2.Text;
      if(!File.Exists(path1))
      {
        MessageBox.Show("文件不存在");
      }
    }
    //瀏覽按鈕
    private void button3_Click(object sender, EventArgs e)
    {
      /*if (folderBrowserDialog1.ShowDialog() == DialogResult.OK)
      {
 
        string selUrl = folderBrowserDialog1.SelectedPath;
      }*/
     
     OpenFileDialog ofd = new OpenFileDialog();
 
      if (ofd.ShowDialog() == DialogResult.OK)
      {
        textBox2.Text = ofd.FileName;
      }
 
      //選擇文件夾
      /* FolderBrowserDialog fbd = new FolderBrowserDialog();
      fbd.ShowDialog();
      MessageBox.Show(fbd.SelectedPath);
       */
    }
    //讀取文件
    private void button1_Click(object sender, EventArgs e)
    {
      if(textBox2.Text!=null)
        //讀取文件內(nèi)容并顯示在textbox1中讓用戶修改 
      {
        string path=textBox2.Text;
        if (File.Exists(path))
       //  {
        //   File.Delete(path);
        // }
        textBox1.Text = File.ReadAllText(path, Encoding.Default);
      }
    }
 
    private void button2_Click(object sender, EventArgs e)
    {
      // string[] appendText=textBox1.Text;
       
      File.WriteAllText(textBox2.Text, textBox1.Text, Encoding.Default);
      MessageBox.Show("保存成功");
    }

  }
}

namespace 文本文件打開(kāi)測(cè)試 
{ 
 public partial class Form1 : Form 
 { 
  public Form1() 
  { 
   InitializeComponent(); 
  } 
  private void btn_Read_Click(object sender, EventArgs e) 
  { 
   //異常檢測(cè)開(kāi)始 
   try
   { 
    FileStream fs = new FileStream(@tB_PachFileName.Text , FileMode.Open, FileAccess.Read);//讀取文件設(shè)定 
    StreamReader m_streamReader = new StreamReader(fs, System.Text.Encoding.GetEncoding("GB2312"));//設(shè)定讀寫(xiě)的編碼 
    //使用StreamReader類(lèi)來(lái)讀取文件 
    m_streamReader.BaseStream.Seek(0, SeekOrigin.Begin); 
    // 從數(shù)據(jù)流中讀取每一行，直到文件的最后一行，并在rTB_Display.Text中顯示出內(nèi)容 
    this.rTB_Display.Text = ""; 
    string strLine = m_streamReader.ReadLine(); 
    while (strLine != null) 
    { 
     this.rTB_Display.Text += strLine + "\n"; 
     strLine = m_streamReader.ReadLine(); 
    } 
    //關(guān)閉此StreamReader對(duì)象 
    m_streamReader.Close(); 
   } 
   catch
   { 
    //拋出異常 
    MessageBox.Show("指定文件不存在"); 
    return; 
   } 
   //異常檢測(cè)結(jié)束 
  } 
  private void btn_Replace_Click(object sender, EventArgs e) 
  { 
   //判斷替換開(kāi)始 
   if (tB_Replace.Text == ""&&tB_Replace_2.Text=="") 
   { 
    MessageBox.Show("想替換的字符都沒(méi)有就換啊,你太有才了"); 
   } 
   else
   { 
    if (rTB_Display.Text == "") 
    { 
     MessageBox.Show("文件內(nèi)容為空無(wú)法進(jìn)行替換,請(qǐng)檢查文件"); 
    } 
    else
    { 
     string str = rTB_Display.Text.ToString(); 
     rTB_Display.Text = str.Replace(@tB_Replace.Text ,@tB_Replace_2.Text);//替換 
    } 
   } 
   //結(jié)束 
  } 
  private void btn_Save_Click(object sender, EventArgs e) 
  { 
   //異常檢測(cè)開(kāi)始 
   try
   { 
    //創(chuàng)建一個(gè)文件流，用以寫(xiě)入或者創(chuàng)建一個(gè)StreamWriter 
    FileStream fs = new FileStream(@tB_Save.Text, FileMode.OpenOrCreate, FileAccess.Write); 
    StreamWriter m_streamWriter = new StreamWriter(fs); 
    m_streamWriter.Flush(); 
    // 使用StreamWriter來(lái)往文件中寫(xiě)入內(nèi)容 
    m_streamWriter.BaseStream.Seek(0, SeekOrigin.Begin); 
    // 把richTextBox1中的內(nèi)容寫(xiě)入文件 
    m_streamWriter.Write(rTB_Display.Text); 
    //關(guān)閉此文件 
    m_streamWriter.Flush(); 
    m_streamWriter.Close(); 
   } 
   catch
   { 
    //拋出異常 
    MessageBox.Show("寫(xiě)入文件失敗,請(qǐng)檢查路徑 文件名與權(quán)限是否符合"); 
   } 
   //異常檢測(cè)結(jié)束 
  } 
 } 
}

//寫(xiě)入文本文件
  class WriteTextFile
  {
    static void Main()
    {
      //如果文件不存在，則創(chuàng)建；存在則覆蓋
      //該方法寫(xiě)入字符數(shù)組換行顯示
      string[] lines = { "first line", "second line", "third line","第四行" };
      System.IO.File.WriteAllLines(@"C:\testDir\test.txt", lines, Encoding.UTF8);

      //如果文件不存在，則創(chuàng)建；存在則覆蓋
      string strTest = "該例子測(cè)試一個(gè)字符串寫(xiě)入文本文件。";
      System.IO.File.WriteAllText(@"C:\testDir\test1.txt", strTest, Encoding.UTF8);

      //在將文本寫(xiě)入文件前，處理文本行
      //StreamWriter一個(gè)參數(shù)默認(rèn)覆蓋
      //StreamWriter第二個(gè)參數(shù)為false覆蓋現(xiàn)有文件，為true則把文本追加到文件末尾
      using (System.IO.StreamWriter file = new System.IO.StreamWriter(@"C:\testDir\test2.txt",true))
      {
        foreach (string line in lines)
        {
          if (!line.Contains("second"))
          {
            file.Write(line);//直接追加文件末尾，不換行
            file.WriteLine(line);// 直接追加文件末尾，換行  
          }
        }
      }
    }
  }

//讀取文本文件

  class ReadTextFile
  {
    static void Main()
    {
      //直接讀取出字符串
      string text = System.IO.File.ReadAllText(@"C:\testDir\test1.txt");
      Console.WriteLine(text);

      //按行讀取為字符串?dāng)?shù)組
      string[] lines = System.IO.File.ReadAllLines(@"C:\testDir\test.txt");
      foreach (string line in lines)
      {
        Console.WriteLine(line);
      }

      //從頭到尾以流的方式讀出文本文件
      //該方法會(huì)一行一行讀出文本
      using (System.IO.StreamReader sr = new System.IO.StreamReader(@"C:\testDir\test.txt"))
      {
        string str;
        while ((str = sr.ReadLine()) != null)
        {
          Console.WriteLine(str);
        }
      }
      Console.Read();
    }
  }