File Handling Classes in C#

What are File Handling Classes in C#?

**File handling** in C# allows reading from and writing to files using various classes available in the System.IO namespace. These classes help perform file operations such as **creating, reading, writing, copying, moving, and deleting files**.

Key File Handling Classes in C#

The following classes are commonly used for file handling in C#:

Class	Description	Example Use Case
`File`	Provides static methods for common file operations.	Checking file existence, copying, or deleting files.
`FileInfo`	Provides instance-based methods for file operations.	Getting file size, extension, or modifying attributes.
`StreamReader`	Reads text from a file line by line.	Reading log files.
`StreamWriter`	Writes text to a file.	Logging application activities.
`FileStream`	Reads and writes bytes from/to a file.	Working with binary data in files.

Creating a File in C#

The File.Create() and FileInfo.Create() methods can be used to create a new file.

Example: Creating a File

using System;
using System.IO;

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

        if (!File.Exists(filePath))
        {
            File.Create(filePath).Close();
            Console.WriteLine("File created successfully.");
        }
        else
        {
            Console.WriteLine("File already exists.");
        }
    }
}

// Output:
// File created successfully. (If file doesn't exist)

The File.Create() method creates a new file, and Close() ensures proper file closure.

Writing to a File

You can write text to a file using the StreamWriter class.

Example: Writing to a File

using System;
using System.IO;

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

        using (StreamWriter writer = new StreamWriter(filePath))
        {
            writer.WriteLine("Hello, File Handling in C#!");
            writer.WriteLine("This is a test file.");
        }

        Console.WriteLine("Text written to file successfully.");
    }
}

// Output:
// Text written to file successfully.

The **using** statement ensures the file is properly closed after writing.

Reading from a File

You can read text from a file using the StreamReader class.

Example: Reading from a File

using System;
using System.IO;

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

        using (StreamReader reader = new StreamReader(filePath))
        {
            string content = reader.ReadToEnd();
            Console.WriteLine("File Content:");
            Console.WriteLine(content);
        }
    }
}

// Output:
// File Content:
// Hello, File Handling in C#!
// This is a test file.

The **ReadToEnd()** method reads the entire content of the file.

Copying and Deleting Files

You can copy or delete files using the File class.

Example: Copying and Deleting Files

using System;
using System.IO;

class Program
{
    static void Main()
    {
        string sourceFile = "example.txt";
        string destinationFile = "copy_example.txt";

        // Copy File
        File.Copy(sourceFile, destinationFile, true);
        Console.WriteLine("File copied successfully.");

        // Delete File
        File.Delete(destinationFile);
        Console.WriteLine("Copied file deleted successfully.");
    }
}

// Output:
// File copied successfully.
// Copied file deleted successfully.

The File.Copy() method duplicates a file, while File.Delete() removes it.

Best Practices for File Handling

Use **using blocks** to ensure files are properly closed after use.
Check **file existence** before performing read/write operations.
Use **exception handling** to manage file access errors.
Avoid **file locks** by properly closing files after use.