Question

I have some code which outputs data from the FileSystemWatcher class, although each times to outputs a line to test.txt, it overwrites the previous entry, is there a way to stop this happening?

Code in question:

static void FileWatcher_Created(object sender, FileSystemEventArgs e)
{

    using (StreamWriter fileWriter = new StreamWriter("test3.txt"))
    {
        var data = true;
        fileWriter.Write("C:\\" + e.Name + Environment.NewLine);
    }

Full Code:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;

namespace FileWatcherr
{
class Program
{    
    static void Main(string[] args)
    {
        string dirPath = "C:\\";
        FileSystemWatcher fileWatcher = new FileSystemWatcher(dirPath); 
        fileWatcher.IncludeSubdirectories = true;  
        fileWatcher.Filter = "*.exe";    
        // fileWatcher.Filter = "C:\\$Recycle.Bin";   
        //  fileWatcher.Changed += new FileSystemEventHandler(FileWatcher_Changed);   
        fileWatcher.Created += new FileSystemEventHandler(FileWatcher_Created);    
        //  fileWatcher.Deleted += new FileSystemEventHandler(FileWatcher_Deleted);  
        //  fileWatcher.Renamed += new RenamedEventHandler(FileWatcher_Renamed);    
        fileWatcher.EnableRaisingEvents = true;      

        // updated code


        Console.ReadKey(); 
    }



        static void FileWatcher_Renamed(object sender, RenamedEventArgs e)
        {
            Console.WriteLine(e.OldName + " was renamed to " + e.Name);
        }

        static void FileWatcher_Deleted(object sender, FileSystemEventArgs e)

        {
            Console.WriteLine(e.Name + " was deleted");
        }

        static void FileWatcher_Created(object sender, FileSystemEventArgs e)
        {

            using (StreamWriter fileWriter = new StreamWriter("test3.txt"))
            {
                var data = true;
                fileWriter.Write("C:\\" + e.Name + Environment.NewLine);
            }

        }

        static void FileWatcher_Changed(object sender, FileSystemEventArgs e)
        {
            Console.WriteLine(e.Name + "");
        }
    }
}

Answer 1

Edit your code to be the below. The second parameter to the StreamWriter is if we should append or overwrite. Set to true to append and false to overwrite (default, thus your problem)

   using (StreamWriter fileWriter = new StreamWriter("test3.txt", true))
    {
        var data = true;
        fileWriter.WriteLine(Path.Combine("C:\\", e.Name));
    }

More info about this constructor can be found here http://msdn.microsoft.com/en-us/library/36b035cb.aspx