经过大量的研究,在阅读并尝试了这里的所有问题之后,我认为是时候寻求一些帮助了。
我有一个 C# 应用程序,我正在尝试使用不同的线程编写相同的文件。
public static void LaunchThreads(string path_file)
{
int i = 0;
Dictionary<int, Thread> threadsdico = new Dictionary<int, Thread>();
while (i < MAX_THREAD)
{
Thread thread = new Thread(() => ThreadEntryWriter(string path_file));
thread.Name = string.Format("ThreadsWriters{0}", i);
threadsdico.Add(i, thread);
thread.Start();
i++;
}
int zz = 0;
while (zz < threadsdico.Count())
{
threadsdico[zz].Join();
zz++;
}
}
private static readonly Object obj = new Object();
public static void ThreadEntryWriter(string path_file)
{
int w = 0;
while (w < 99)
{
string newline = w + " - test" + "r";
lock(obj)
{
string txt = File.ReadAllText(path_file);
using (TextWriter myWriter = new StreamWriter(path_file))
{
TextWriter.Synchronized(myWriter).Write(txt + newline);
}
}
w++;
}
}
我已经尝试了一切,我的代码是全局的,但是我已经尝试了各种方式,每个锁,每个文件打开方法,但我不断得到The process cannot access the files because it's in use
.产生此错误的行是这个using (TextWriter myWriter = new StreamWriter(path_file))
。
我尝试了很多东西,关闭文件等,但是当线程同时开始工作时,程序停止并The process cannot access the files because it's in use
给我错误(不言自明)。但我不明白为什么,锁应该阻止另一个线程进入这里。我使用同步方法编写线程安全的方法。很抱歉写得太长了,这是我在这里的第一篇文章。
仍然应该释放同步编写器:
var newline = w + " - test";
using (var sw = new StreamWriter(path_file))
using (var sync = TextWriter.Synchronized(sw))
{
// no need to add a new line char, just use other method to write
sync.WriteLine(txt + newline);
}
此外,您可以保存一个sync
变量并从所有线程调用它的方法,它将为您完成所有工作,您可以在编写完所有文本后处理它。
我测试了您的代码并应用了一些更改,它工作正常,没有错误。
我使用 winform 应用程序来运行您的代码。请检查下面的代码。
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
using System.Windows.Forms;
namespace WindowsFormsApplication14
{
public partial class Form1 : Form
{
private readonly Object obj = new Object();
public Form1()
{
InitializeComponent();
}
private void Form1_Load(object sender, EventArgs e)
{
}
private void button1_Click(object sender, EventArgs e)
{
LaunchThreads("D:\log.txt");
}
public void LaunchThreads(string path_file)
{
int i = 0;
int MAX_THREAD = 10;
Dictionary<int, Thread> threadsdico = new Dictionary<int, Thread>();
while (i < MAX_THREAD)
{
Thread thread = new Thread(() => ThreadEntryWriter(path_file, string.Format("ThreadsWriters{0}", i)));
thread.Name = string.Format("ThreadsWriters{0}", i);
threadsdico.Add(i, thread);
thread.Start();
i++;
}
int zz = 0;
while (zz < threadsdico.Count())
{
threadsdico[zz].Join();
zz++;
}
}
public void ThreadEntryWriter(string path_file,string threadName)
{
int w = 0;
while (w < 99)
{
string newline = w + " - test" + " Thread:" + threadName + "rn";
lock (obj)
{
string txt = File.ReadAllText(path_file);
using (TextWriter myWriter = new StreamWriter(path_file))
{
TextWriter.Synchronized(myWriter).Write(txt + newline);
}
}
w++;
}
}
}
}
我得到了如下输出。
- 0 - 测试线程:线程编写器1
- 0 - 测试线程:线程编写器2
- 1 - 测试线程:线程编写器2
- 2 - 测试线程:线程编写器2
- 1 - 测试线程:线程编写器1
- ....
- ....
似乎您想从多个线程将行写入同一文件。
每次要输出一行然后附加一行并将其写出时,读取所有行的效率非常低。
我认为您错误的原因是您没有处理同步的文本编写器,因此即使您处理了底层文本编写器,它也可能会保持对文件的引用处于打开状态。
使用自己的锁定和同步文本编写器也是多余的。
我已经对您的代码进行了一些更改,以共享单个同步文本编写器,并且仅附加行而不是读取整个文件,附加然后写出:
public static void LaunchThreads(string path_file)
{
int i = 0;
using(var sw = File.CreateText(path_file))
using(var syncWriter = TextWriter.Synchronized(sw))
{
Dictionary<int, Thread> threadsdico = new Dictionary<int, Thread>();
while (i < MAX_THREAD)
{
Thread thread = new Thread(() => ThreadEntryWriter(syncWriter));
thread.Name = string.Format("ThreadsWriters{0}", i);
threadsdico.Add(i, thread);
thread.Start();
i++;
}
int zz = 0;
while (zz < threadsdico.Count())
{
threadsdico[zz].Join();
zz++;
}
}
}
public static void ThreadEntryWriter(TextWriter writer)
{
int w = 0;
while (w < 99)
{
writer.WriteLine($"{w} - test");
w++;
}
}