What class would you use to read a file line-by-line?

Question

Utpal Vishwas · Answer

To read a file line by line in C#, you commonly use the 
StreamReader class.
Best Class: System.IO.StreamReader
Example:
using System;
using System.IO;
class Program
{
    static void Main()
    {
        using (StreamReader reader = new StreamReader("file.txt"))
        {
            string? line;
            while ((line = reader.ReadLine()) != null)
            {
                Console.WriteLine(line);
            }
        }
    }
}
StreamReader.ReadLine() reads one line at a time.The using statement ensures the file is closed properly after reading.
Alternative: File.ReadLines()
For simpler cases, you can use File.ReadLines(), which is more concise and memory-efficient for large files:
foreach (string line in File.ReadLines("file.txt"))
{
    Console.WriteLine(line);
}
Also reads lazily (line by line), unlike File.ReadAllLines() which reads the entire file at once.
Summary
Class/Method
Description
Reads Line-by-Line?
StreamReader
Low-level, full control
Yes
File.ReadLines()
Recommended for simplicity
Yes
File.ReadAllLines()
Loads all lines into memory array
No (not lazy)
and

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What class would you use to read a file line-by-line?

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1 Answers

Best Class: `System.IO.StreamReader`

Example:

Alternative: `File.ReadLines()`

Summary

Liked By

Class/Method	Description	Reads Line-by-Line?
`StreamReader`	Low-level, full control	Yes
`File.ReadLines()`	Recommended for simplicity	Yes
`File.ReadAllLines()`	Loads all lines into memory array	No (not lazy)