c#如何向C++那样把一个文件拆成几个文件

切割文件？
刚好我这里有代码
if (args[0] == "s")
{
int i;

FileStream fr = new FileStream(args[1], FileMode.Open, FileAccess.Read);
int FileSize = Convert.ToInt32(fr.Length) / Convert.ToInt32(args[2]);
StreamWriter fwlist = new StreamWriter(args[1] + "." + "list", false);

for (i = 1; i <= Convert.ToInt32(args[2]); i++)
{
byte[] byteread = new byte[FileSize];

fr.Read(byteread, 0, FileSize);

FileStream fw = new FileStream(args[1] + "." + i, FileMode.CreateNew, FileAccess.Write);

fwlist.WriteLine(args[1] + "." + i);

foreach (byte bNext in byteread)

fw.WriteByte(bNext);