FileStream(String, FileMode)：
FileStream(String, FileMode, FileAccess)
FileStream(String, FileMode, FileAccess, FileShare)
FileStream(String, FileMode, FileAccess, FileShare, Int32)

FileStream devStream = new FileStream(devPath, FileMode.Append, FileAccess.Write, FileShare.ReadWrite,512);
devStream.Write(data, 0, 128);
 
if(devStream != null)
 devStream.Close();

public static class MonitData
{
 public static string devPath = string.Empty;
 private static object objLock = new object();
 public static void WriteInfo(byte[] data)
 {
  lock (objLock)
  {
   if (!string.IsNullOrEmpty(devPath))
   {
    byte[] byteArray = new byte[128];
    Array.Copy(data, 0, byteArray, 0, 128);
    if (byteArray != null && byteArray.Length == 128)
    {
      using (System.IO.FileStream fs = System.IO.File.OpenWrite(devPath))
      {
       fs.Seek(0, SeekOrigin.End);
       fs.Write(byteArray, 0, byteArray.Length);
       fs.Close();
       fs.Dispose();
      }
    }
   }
  } 
 }
}

public static void Main(string[] args)
{
 String str = @"E:\下載\軟件";
 Stopwatch sw = new Stopwatch();
 sw.Start();
 using (FileStream fsWriter = new FileStream(str + @"\opencv-3.0.exe", FileMode.Create, FileAccess.Write))
 {
  using (FileStream fsReader = new FileStream(str + @"\opencv-2.4.9.exe", FileMode.Open, FileAccess.Read))
  {
   byte[] bytes=new byte[1024*4];//4kB是合適的；
   int readNum;
   while((readNum=fsReader.Read(bytes,0,bytes.Length))!=0)//小于說明讀完了
   {
    fsWriter.Write(bytes,0,readNum);
    fsWriter .Flush();//清除緩沖區(qū)，把所有數(shù)據(jù)寫入文件中
    fsWriter.Close();
    fsWriter.Dispose();
   }
  }
 }
 sw.Stop();
 Console.WriteLine("總的運(yùn)行時(shí)間為{0}",sw.ElapsedMilliseconds);
 Console.ReadKey();
}

public static string FileStreamReadFile(string filePath)
{
 byte[] data = new byte[100];
 char[] charData = new char[100];
 FileStream file = new FileStream(filePath, FileMode.Open);
 //文件指針指向0位置
 file.Seek(0, SeekOrigin.Begin);//可以設(shè)置第一個(gè)參數(shù)
 //讀入兩百個(gè)字節(jié)
 file.Read(data, 0, (int) file.Length);
 //提取字節(jié)數(shù)組
 Decoder dec = Encoding.UTF8.GetDecoder();
 dec.GetChars(data, 0, data.Length, charData, 0);
 file.Close(); 
 file.Dispose();
 return Convert.ToString(charData);
}