// 寫操作
        public static void Write()
        {
            // 統(tǒng)計寫入（讀取的行數(shù)）
            int WriteRows = 0;

            // 讀取文件的源路徑及其讀取流
            string strReadFilePath = @"..\..\data\ReadLog.txt";
            StreamReader srReadFile = new StreamReader(strReadFilePath);

            // 寫入文件的源路徑及其寫入流
            string strWriteFilePath = @"..\..\data\WriteLog.txt";
            StreamWriter swWriteFile = File.CreateText(strWriteFilePath);

            // 讀取流直至文件末尾結束，并逐行寫入另一文件內
            while (!srReadFile.EndOfStream)
            {
                string strReadLine = srReadFile.ReadLine(); //讀取每行數(shù)據
                ++WriteRows; //統(tǒng)計寫入（讀?。┑臄?shù)據行數(shù)

                swWriteFile.WriteLine(strReadLine); //寫入讀取的每行數(shù)據
                Console.WriteLine("正在寫入... " + strReadLine);
            }

            // 關閉流文件
            srReadFile.Close();
            swWriteFile.Close();

            Console.WriteLine("共計寫入記錄總數(shù)：" + WriteRows);
            Console.ReadKey();
        }

========================================================================

完整源代碼（經過本人測試，直接運行就可）

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

using System.IO; // 引用輸入輸出操作的命令空間

namespace ReadWriteFile
{
    class Program
    {

        // 主函數(shù)
        static void Main(string[] args)
        {
            Read(); // 讀操作

            Write(); // 寫操作
        }

        // 讀操作
        public static void Read()
        {
            // 讀取文件的源路徑及其讀取流
            string strReadFilePath = @"..\..\data\ReadLog.txt";
            StreamReader srReadFile = new StreamReader(strReadFilePath);

            // 讀取流直至文件末尾結束
            while (!srReadFile.EndOfStream)
            {
                string strReadLine = srReadFile.ReadLine(); //讀取每行數(shù)據
                Console.WriteLine(strReadLine); //屏幕打印每行數(shù)據
            }

            // 關閉讀取流文件
            srReadFile.Close();
            Console.ReadKey();
        }

        // 寫操作
        public static void Write()
        {
            // 統(tǒng)計寫入（讀取的行數(shù)）
            int WriteRows = 0;

            // 讀取文件的源路徑及其讀取流
            string strReadFilePath = @"..\..\data\ReadLog.txt";
            StreamReader srReadFile = new StreamReader(strReadFilePath);

            // 寫入文件的源路徑及其寫入流
            string strWriteFilePath = @"..\..\data\WriteLog.txt";
            StreamWriter swWriteFile = File.CreateText(strWriteFilePath);

            // 讀取流直至文件末尾結束，并逐行寫入另一文件內
            while (!srReadFile.EndOfStream)
            {
                string strReadLine = srReadFile.ReadLine(); //讀取每行數(shù)據
                ++WriteRows; //統(tǒng)計寫入（讀取）的數(shù)據行數(shù)

                swWriteFile.WriteLine(strReadLine); //寫入讀取的每行數(shù)據
                Console.WriteLine("正在寫入... " + strReadLine);
            }

            // 關閉流文件
            srReadFile.Close();
            swWriteFile.Close();

            Console.WriteLine("共計寫入記錄總數(shù)：" + WriteRows);
            Console.ReadKey();
        }
    }
}