同时读 - 写在C＃中的文件 [英] simultaneous read-write a file in C#

问题描述

我有一个包含文件，我想监视变化，以及添加自己的变化的数据。认为像尾巴-f foo.txt的。

I have a file containing data that I'd like to monitor changes to, as well as add changes of my own. Think like "Tail -f foo.txt".

根据这个线程，它看起来像我应该只创建一个文件流，它都传递给作者和读者。然而，当读取器到达原始文件的末尾时，它未能看到我写自己的更新。

Based on this thread, it looks like I should just create a filestream, and pass it both to a writer and reader. However, when the reader reaches the end of the original file, it fails to see updates I write myself.

我知道这似乎是一个奇怪的情况...查看其更多的实验，如果是可以做到的。

I know it seems like a weird situation... its more an experiment to see if it can be done.

下面是我试过的例子情况：

Here is the example case I tried:

foo.txt的：结果
一个结果
b结果
ç结果
ð结果
Ë结果
˚F结果

foo.txt:
a
b
c
d
e
f

        string test = "foo.txt";
        System.IO.FileStream fs = new System.IO.FileStream(test, System.IO.FileMode.OpenOrCreate, System.IO.FileAccess.ReadWrite);

        var sw = new System.IO.StreamWriter(fs);
        var sr = new System.IO.StreamReader(fs);

        var res = sr.ReadLine();
        res = sr.ReadLine();
        sw.WriteLine("g");
        sw.Flush();
        res = sr.ReadLine();
        res = sr.ReadLine();
        sw.WriteLine("h");
        sw.Flush();
        sw.WriteLine("i");
        sw.Flush();
        sw.WriteLine("j");
        sw.Flush();
        sw.WriteLine("k");
        sw.Flush();
        res = sr.ReadLine();
        res = sr.ReadLine();
        res = sr.ReadLine();
        res = sr.ReadLine();
        res = sr.ReadLine();
        res = sr.ReadLine();

让过去的F后，读者将返回null。

After getting past "f", the reader returns null.

推荐答案

好吧，两名编辑后...

Ok, two edits later...

这应该工作。我第一次尝试它，我想我已经忘记设置FileMode.Append对ostream的。

This should work. The first time I tried it I think I had forgotten to set FileMode.Append on the oStream.

string test = "foo.txt";

var oStream = new FileStream(test, FileMode.Append, FileAccess.Write, FileShare.Read); 
var iStream = new FileStream(test, FileMode.Open, FileAccess.Read, FileShare.ReadWrite); 

var sw = new System.IO.StreamWriter(oStream);
var sr = new System.IO.StreamReader(iStream); 
var res = sr.ReadLine(); 
res = sr.ReadLine();
sw.WriteLine("g"); 
sw.Flush(); 
res = sr.ReadLine();
res = sr.ReadLine();
sw.WriteLine("h"); sw.Flush();
sw.WriteLine("i"); sw.Flush(); 
sw.WriteLine("j"); sw.Flush(); 
sw.WriteLine("k"); sw.Flush(); 
res = sr.ReadLine(); 
res = sr.ReadLine(); 
res = sr.ReadLine();
res = sr.ReadLine();
res = sr.ReadLine();
res = sr.ReadLine();

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