Đọc ghi file .txt trong c# với visual studio 2010

Code đọc dữ liệu từ file .txt trong c#.
Code ghi dữ liệu vào file .txt c#.
Đây là toàn bộ code đọc ghi file .txt trong c# sử dụng visual studio

Mã:

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

namespace CheckIP
{
    public partial class CheckIP : Form
    {
        private OpenFileDialog FileOpen = new OpenFileDialog();
        private string chooseFile;
        public CheckIP()
        {
          
            InitializeComponent();
            this.MaximizeBox = false;
            this.StartPosition = FormStartPosition.CenterScreen;
            FileOpen.FileOk += new CancelEventHandler(FileOpen_FileOk);
        }

        void FileOpen_FileOk(object sender, CancelEventArgs e)
        {
            chooseFile = FileOpen.FileName;
            this.Text = Path.GetFileName(chooseFile);
            DisplayFile();
        }

        private void CheckIP_Load(object sender, EventArgs e)
        {
            FileOpen.ShowDialog(); // mở file
        }
 // đọc file start    
        private void DisplayFile()
        {
            int nCols = 16;
            FileStream inStream = new FileStream(chooseFile, FileMode.Open,
                                                             FileAccess.Read);
            long nBytesToRead = inStream.Length;
            if (nBytesToRead > 65536 / 4)
                nBytesToRead = 65536 / 4;
            int nLines = (int)(nBytesToRead / nCols) + 1;
            string[] lines = new string[nLines];
            int nBytesRead = 0;
            for (int i = 0; i < nLines; i++)
            {
                StringBuilder nextLine = new StringBuilder();
                nextLine.Capacity = 4 * nCols;
                for (int j = 0; j < nCols; j++)
                {
                    int nextByte = inStream.ReadByte();
                    nBytesRead++;
                    if (nextByte < 0 || nBytesRead > 65536)
                        break;
                    char nextChar = (char)nextByte;
                    if (nextChar < 16)
                        nextLine.Append(" x0" + string.Format("{0,1:X}",
                                                             (int)nextChar));
                    else if (char.IsLetterOrDigit(nextChar) ||
                                             char.IsPunctuation(nextChar))
                        nextLine.Append(" " + nextChar + " ");
                    else nextLine.Append(" x" + string.Format("{0,2:X}",
                                               (int)nextChar));
                }
                lines[i] = nextLine.ToString();
            }

            inStream.Close();

            richTextBox.Lines = lines;
        }
// đọc file end
// ghi file start
        void SaveFile()
        {
            StreamWriter sw = new StreamWriter(chooseFile, false,
                                  Encoding.Unicode);
            foreach (string line in richTextBox.Lines)
                sw.WriteLine(line);
            sw.Close();
        }
// ghi file end
        
    }
}

Demo

Download code trên từ link mediafire về.

Code được viết trên visual 10, dnet 4.0