(原) .NET 读写大文件

using System;
using System.IO;

class FStream
{
    private const int SIZE = 1024;
  
    static void Main()
    {
        DealBigFile(@"C:\Kit.rar");
    }

    // 处理大文件
    public static void DealBigFile(string fileName)
    {
        using (FileStream fileStream = new FileStream(fileName, FileMode.Open ,FileAccess.Read))
        {
            int offset=0;
            int count = 0;
            do{
                byte[] dataArray = new byte[SIZE];
                count = fileStream.Read(dataArray, 0, SIZE);
                offset += count;

                // 计算处理后，即dataArray发生变化
                // ..

                WriteFile(@"C:\2.rar", dataArray);
            }while(count==SIZE);
            fileStream.Close();
            fileStream.Dispose();
        }
    }

    // 写入文件（追加的形式）
    public static void WriteFile(string fileName, byte[] array)
    {
        using (FileStream fileStream = new FileStream(fileName, FileMode.OpenOrCreate, FileAccess.Write))
        {
            fileStream.Seek(fileStream.Length, 0);
            fileStream.Write(array, 0, array.Length);
            fileStream.Flush();
            fileStream.Close();
            fileStream.Dispose();
        }
    }
}