Writing text files in C Sharp (C#)

Introduction

Writing text files lets your program save information on the computer. This way, you can keep data even after the program stops.

Saving user notes or documents from an app

Logging events or errors while a program runs

Exporting data like lists or reports for later use

Creating configuration files that the program reads next time

Syntax

C Sharp (C#)

using System.IO;

File.WriteAllText("filename.txt", "Your text here");

The File.WriteAllText method writes all text to a file at once.

If the file does not exist, it will be created automatically.

Examples

This writes the text "Hello, world!" to a file named hello.txt.

C Sharp (C#)

File.WriteAllText("hello.txt", "Hello, world!");

You can use variables for the file name and content to make the code clearer.

C Sharp (C#)

string path = "notes.txt";
string content = "Remember to buy milk.";
File.WriteAllText(path, content);

Use escape sequences like \n to add new lines inside the text.

C Sharp (C#)

File.WriteAllText("log.txt", "Error at line 10\n");

Sample Program

This program writes "Hello from C#!" to a file named greeting.txt. Then it tells you the file was written.

C Sharp (C#)

using System;
using System.IO;

class Program
{
    static void Main()
    {
        string filename = "greeting.txt";
        string message = "Hello from C#!";

        File.WriteAllText(filename, message);

        Console.WriteLine($"Text written to {filename}");
    }
}

Important Notes

Make sure your program has permission to write files in the folder you choose.

Using File.WriteAllText replaces the whole file content. To add text without erasing, use File.AppendAllText.

Summary

Writing text files saves data permanently on your computer.

Use File.WriteAllText to create or overwrite a text file easily.

Remember to handle file paths and permissions carefully.