Working with Text Streams in C#: A Guide to the `TextReader` Class

Learn how to use C#'s `TextReader` class for efficient and flexible text stream processing. This tutorial explains its role as an abstract base class, demonstrates its use with `StreamReader` and `StringReader` for reading text from files and strings, and highlights best practices for handling text data.

Working with C#'s `TextReader` Class

The C# `TextReader` class is an abstract base class representing a reader that obtains characters from a text stream. It's a fundamental class for reading text data sequentially from various sources, like files or strings.

Understanding `TextReader`

The `TextReader` class (part of the `System.IO` namespace) provides methods for reading character data. It doesn't directly work with files; instead, you'd typically use a class like `StreamReader` (to read from a file) or `StringReader` (to read from a string) which inherit from `TextReader`.

Example 1: Reading All Data from a File

This example reads the entire content of a file into a string using `File.OpenText()` and `TextReader.ReadToEnd()`:

using System;
using System.IO;

public class TextReaderExample {
    public static void Main(string[] args) {
        string filePath = "mytextfile.txt";
        using (TextReader reader = File.OpenText(filePath)) {
            string fileContent = reader.ReadToEnd();
            Console.WriteLine(fileContent);
        }
    }
}

The `using` statement ensures that the `TextReader` is properly closed even if exceptions occur.

Example 2: Reading One Line from a File

This example reads a single line from a file using `TextReader.ReadLine()`:

using System;
using System.IO;

public class TextReaderExample {
    public static void Main(string[] args) {
        string filePath = "mytextfile.txt";
        using (TextReader reader = File.OpenText(filePath)) {
            string line = reader.ReadLine();
            Console.WriteLine(line);
        }
    }
}