Services
Technology Web App Development Mobile App Development Windows App Development Database Development UI/UX Development Cloud Development SEO Digital Marketing Guest Posting Content Writing Artificial Intelligence Data Science ERP Development CRM Development CMS Development LMS Development Business Listing Blockchain Technology Startup Promotion AI Tools Integration
Products
Data Converter Cleaner TUC - Unit Converter Import Export Survey Manager Tweet Controller
Developer
Article Blog Forum Interview Beginner News Startup Quiz
Users
Career
Apply Job Internship
Pricing
Login Sign Up Get a Quote

interview

Home Interviews How can you watch for file changes like creation or deletion in real-time? – MindStick
Ask Question

1 Answers

ICSM Computer
ICSM Computer 08 May 2025
Report Abuse

To watch for file changes (like creation, deletion, or modification) in real-time in C#, you can use the built-in FileSystemWatcher class in the System.IO namespace.

Example: Monitor a directory for changes

using System;
using System.IO;

class Program
{
    static void Main()
    {
        string pathToWatch = @"C:\MyFolder";

        using (FileSystemWatcher watcher = new FileSystemWatcher(pathToWatch))
        {
            // Watch for changes in LastWrite times, and creation/deletion of files
            watcher.NotifyFilter = NotifyFilters.FileName | NotifyFilters.LastWrite | NotifyFilters.CreationTime;

            // Only watch text files
            watcher.Filter = "*.txt";

            // Event handlers
            watcher.Created += OnCreated;
            watcher.Deleted += OnDeleted;
            watcher.Changed += OnChanged;
            watcher.Renamed += OnRenamed;

            // Begin watching
            watcher.EnableRaisingEvents = true;

            Console.WriteLine("Watching for changes. Press Enter to exit...");
            Console.ReadLine();  // Keep the program running
        }
    }

    private static void OnCreated(object sender, FileSystemEventArgs e) =>
        Console.WriteLine($"File created: {e.FullPath}");

    private static void OnDeleted(object sender, FileSystemEventArgs e) =>
        Console.WriteLine($"File deleted: {e.FullPath}");

    private static void OnChanged(object sender, FileSystemEventArgs e) =>
        Console.WriteLine($"File changed: {e.FullPath}");

    private static void OnRenamed(object sender, RenamedEventArgs e) =>
        Console.WriteLine($"File renamed: {e.OldFullPath} -> {e.FullPath}");
}

Notes:

  • FileSystemWatcher supports events: Created, Deleted, Changed, and Renamed.
  • Use IncludeSubdirectories = true to monitor subfolders.
  • It's best suited for local directories (not reliable over network shares).
advertising
Markdown for AI

A clean, structured version of this page for AI assistants and LLMs.

Open .md