File I/O in C# Language

File Input/Output (I/O) is a fundamental aspect of any programming language, including C#. It allows you to

read data from files, write data to files, and manipulate file content. In C#, file I/O operations are made straightforward and powerful with a rich set of classes and methods in the .NET framework. In this post, we will explore how to perform common file I/O operations in C# with examples.

Reading from a File

To read data from a file in C#, you can use the File and StreamReader classes. Here’s an example of how to read text from a file:

using System;
using System.IO;

class Program
{
    static void Main()
    {
        string filePath = "example.txt";

        try
        {
            using (StreamReader reader = new StreamReader(filePath))
            {
                string line;
                while ((line = reader.ReadLine()) != null)
                {
                    Console.WriteLine(line);
                }
            }
        }
        catch (IOException e)
        {
            Console.WriteLine("An error occurred: " + e.Message);
        }
    }
}

In this example, we use a StreamReader to open and read from the file “example.txt” line by line.

Writing to a File

To write data to a file, you can use the File and StreamWriter classes. Here’s an example of how to write text to a file:

using System;
using System.IO;

class Program
{
    static void Main()
    {
        string filePath = "output.txt";

        try
        {
            using (StreamWriter writer = new StreamWriter(filePath))
            {
                writer.WriteLine("Hello, World!");
                writer.WriteLine("This is a sample text.");
            }

            Console.WriteLine("Data has been written to the file.");
        }
        catch (IOException e)
        {
            Console.WriteLine("An error occurred: " + e.Message);
        }
    }
}

In this example, we create a StreamWriter to write text to the file “output.txt.”

Checking File Existence

You can check if a file exists using the File.Exists method. Here’s an example:

using System;
using System.IO;

class Program
{
    static void Main()
    {
        string filePath = "example.txt";

        if (File.Exists(filePath))
        {
            Console.WriteLine("File exists!");
        }
        else
        {
            Console.WriteLine("File does not exist.");
        }
    }
}

This code checks if the file “example.txt” exists in the current directory.

Additional File I/O Operations

C# provides a wide range of file I/O operations beyond basic reading and writing, including file copying, moving, deleting, and more. These operations can be performed using classes such as File, Directory, and Path from the System.IO namespace.