Why am I getting an Unhandled Exception: System.IO.IOException when I try to read from the file it is written to?

Question

I have two C # applications, one of them reads a file (file A) line by line and writes its contents to another file (file B).

The second application uses FileSystemWatcher for file B to see when it is updated and to report the difference between line numbers between when the program was launched and when the file was changed.

That’s all I’m trying to do now, ultimately I want to read the lines between when the last file was read and the current read, but until I get the difference in the standby line.

The code that I have for application 1 is:

        static void Main(string[] args)
    {
        String line;

        StreamReader sr = new StreamReader("f:\\watch\\input.txt");

        FileStream fs = new FileStream("f:\\watch\\Chat.log", FileMode.Create, FileAccess.Write, FileShare.ReadWrite);
        StreamWriter sw = new StreamWriter(fs);

        while ((line = sr.ReadLine()) != null)
        {
            sw.WriteLine(line);
            Thread.Sleep(200);
            Console.WriteLine(line);
            sw.Flush();

        }

        sw.Close();
        sr.Close();

    }

The code I have for application 2 is:

        public static int lines = 0;

    public static void Main()
    {
        Run();
    }

    public static void Run()
    {
        string[] args = System.Environment.GetCommandLineArgs();

        if (args.Length != 2)
        {
            Console.WriteLine("Usage: Watcher.exe (directory)");
            return;
        }

FileSystemWatcher watcher = new FileSystemWatcher();
watcher.Path = args[1];

watcher.NotifyFilter = NotifyFilters.LastAccess | NotifyFilters.LastWrite 
   | NotifyFilters.FileName | NotifyFilters.DirectoryName;

watcher.Filter = "Chat.log";

watcher.Changed += new FileSystemEventHandler(OnChanged);

watcher.EnableRaisingEvents = true;

lines = File.ReadAllLines(args[1] + "\\Chat.log").Length;

Console.WriteLine("File lines: " + lines);

while(Console.Read()!='q');
}

private static void OnChanged(object source, FileSystemEventArgs e)
{
    Linework(e.FullPath);
    Console.WriteLine("File: " +  e.FullPath + " " + e.ChangeType);
}

public static string Linework(string path)

{



   string newstring = " ";

using (FileStream stream = new FileStream(path, FileMode.Open, FileAccess.Read, FileShare.ReadWrite))
{
    int newlines = File.ReadAllLines(path).Length;
    Console.WriteLine("Lines now: " + newlines);
}

return newstring;

}

, , : "Unhandled Exception: System.IO.IOException: , ".

ReadWrite, FileAccess.Write, FileAccess.Read.

, ?

Hew.

Answer 1

lines = File.ReadAllLines(args [1] + "\ Chat.log" ). ;

. , . "" FileShare.Read. , .

, . . IOException.

File.ReadAllLines() , FileStream FileShare.ReadWrite, StreamReader .

, , , , , . \r, \n . , . , Flush() , , .

Answer 2

ReadWrite .

//lines = File.ReadAllLines(args[1] + "\\Chat.log").Length;
//Commenting the above lines as this would again open a new filestream on the chat.log
//without the proper access mode required.


    using (FileStream fsReader = new FileStream(args[1] + "\\Chat.log", FileMode.Open, FileAccess.ReadWrite, FileShare.ReadWrite))
        {
            using (StreamReader sr = new StreamReader(fsReader))
            {
                while (sr.ReadLine() != null)
                    lines++;
            }
        }

Answer 3

MSDN :

FileStream , SafeFileHandle FileStream SafeFileHandle .

, :

FileStream SafeFileHandle , FileStream ( inline IO, ).

Answer 4

StreamReader sr = new StreamReader("f:\\watch\\input.txt");

input.txt ?

using Close() ( ).

. ( ).

:

int newlines = File.ReadAllLines(path).Length;

stream StreamReader .