Getting file name using FileSystemWatcher and FileSystemEventArgs

Question

I have a problem as to monitoring a file updated in the directory while using FileSystemWatcher and FileSystemEventArgs.
The path's text of the file that is caught by FileSystemEventHandler becomes an unexpected format.
The code is as follow;

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

namespace WatcherTest
{
    class Watcher
    {  
        public Watcher()
        {
            fileSystemWatcher.Filter = "";
            fileSystemWatcher.NotifyFilter = NotifyFilters.LastWrite;
            fileSystemWatcher.Changed += new FileSystemEventHandler(OnChanged);
            fileSystemWatcher.EnableRaisingEvents = true;
        }
        private FileSystemWatcher fileSystemWatcher = new FileSystemWatcher(@"C:\Users\ntsol\Documents\test1");

        public void OnChanged(object obj,FileSystemEventArgs eventArgs)
        {
            Console.WriteLine(eventArgs.FullPath);
            //file name is test.xlsx therefore "C:\Users\ntsol\Documents\test1\test.xlsx" is expected 
            //but "C:\Users\ntsol\Documents\test1\94F7AF00" is displayed  
        }
    }
}

As above,the the part of file name in the path that is displayed is unexpected format.
Any help on this would be appreciated.

Answer 1

Hi ntsol-5133,
When you save an xlsx file, it writes the data to a temporary file and then "moves" it to the final directory, which may be triggered by a "rename" event.
My test also proved this and please refer to the following code.

    FileSystemWatcher fileSystemWatcher = new FileSystemWatcher(@"C:\Users\Desktop\excle");  
    fileSystemWatcher.Filter = "";          
    fileSystemWatcher.NotifyFilter = NotifyFilters.LastWrite |  
                    NotifyFilters.DirectoryName | NotifyFilters.FileName |  
                    NotifyFilters.Size;  
    fileSystemWatcher.Renamed += new RenamedEventHandler(OnRenamed);  
    fileSystemWatcher.EnableRaisingEvents = true;  
  
private static void OnRenamed(object source, RenamedEventArgs e)  
{  
    // Specify what is done when a file is renamed.  
    //Console.WriteLine("File: {0} renamed to {1}", e.OldFullPath, e.FullPath);  
    Console.WriteLine("File:{0}", e.FullPath);  
}  

Best Regards,
Daniel Zhang

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Answer 2

Using the following:

class Program
{
    static AutoResetEvent e = new AutoResetEvent(false);

    static void Main(string[] args)
    {
        FileSystemWatcher fileSystemWatcher = new FileSystemWatcher(@"G:\Temporary");
        fileSystemWatcher.Filter = "";
        fileSystemWatcher.NotifyFilter = NotifyFilters.LastWrite;
        fileSystemWatcher.Changed += new FileSystemEventHandler(OnChanged);
        fileSystemWatcher.EnableRaisingEvents = true;
        e.WaitOne();
    }

    static public void OnChanged(object obj, FileSystemEventArgs eventArgs)
    {
        Console.WriteLine(eventArgs.FullPath);
        e.Set();
    }

}

In my system when I change G:\Temporary\t.txt I get:

G:\Temporary\t.txt

Answer 3

The reason is no changed event triggered when excel save his document !
He saves a new temporary file and he renames it to your xlsx filename.
You must managed the "renamed" event