這裏是我的代碼:爲什麼線程無法正常工作?
using System;
using System.Collections;
using System.Collections.Generic;
using System.Collections.Concurrent;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;
using System.IO;
using System.IO.MemoryMappedFiles;
namespace CopyFile
{
class Program
{
static void Main()
{
long length = 0;
byte[] buffer;
string source_path, dest_path;
source_path = Console.ReadLine();
dest_path = Console.ReadLine();
FileInfo fi = new FileInfo(source_path);
length = (int)fi.Length;
// Create disk file
using (FileStream fs = File.Create(dest_path))
{
fs.Close();
}
// Create unnamed MMF
var mmf1 = MemoryMappedFile.CreateFromFile(source_path, FileMode.OpenOrCreate, null, length);
// Create reader to MMF
var reader = mmf1.CreateViewAccessor(0, length, MemoryMappedFileAccess.Read);
// Create unnamed MMF
var mmf2 = MemoryMappedFile.CreateFromFile(dest_path, FileMode.Create, null, length);
// Create writer to MMF
var writer = mmf2.CreateViewAccessor(0, length, MemoryMappedFileAccess.Write);
int read_block = int.Parse(Math.Min(length, 512 * 1024).ToString());//4k
int end_read_block = int.Parse(length.ToString()) % read_block;
int[] offset_array = new int[int.Parse((length - read_block).ToString())/read_block];
for (int offset = 0,i=0; i < int.Parse((length - read_block).ToString())/read_block; i++,offset += read_block)
{
offset_array[i] = offset;
}
/*
Parallel.ForEach<int>(offset_array, offset =>
{
// Read from MMF
buffer = new byte[read_block];
reader.ReadArray<byte>(offset, buffer, 0, read_block);
// Write to MMF
writer.WriteArray<byte>(offset, buffer, 0, read_block);
});
*/
foreach (int offset in offset_array)
{
// Read from MMF
buffer = new byte[read_block];
reader.ReadArray<byte>(offset, buffer, 0, read_block);
// Write to MMF
writer.WriteArray<byte>(offset, buffer, 0, read_block);
}
buffer = new byte[end_read_block];
reader.ReadArray<byte>(length - end_read_block, buffer, 0, end_read_block);
// Write to MMF
writer.WriteArray<byte>(length - end_read_block, buffer, 0, end_read_block);
}
}
}
我嘗試複製一個文件,並將其粘貼到另一個位置 它正在
但是當我嘗試使用Parallel.foreach或時的Parallel.For複製一個文件 複製的文件與源文件不同
(我評論Parallel.foreach部分)
我不明白爲什麼
謝謝
它將如何工作?如果您有多個線程寫入它,您將會寫入該文件。 – steveg89 2012-08-15 16:27:44