---
title: "Explain the difference between StreamReader and File.ReadAllLines()."  
description: "Explain the difference between StreamReader and File.ReadAllLines()."  
author: "ICSM Computer"  
published: 2025-05-05  
updated: 2025-05-19  
canonical: https://www.mindstick.com/forum/161576/explain-the-difference-between-streamreader-and-file-readalllines  
category: "c#"  
tags: ["c#", "file handling"]  
reading_time: 2 minutes  

---

# Explain the difference between StreamReader and File.ReadAllLines().

[Explain the difference](https://www.mindstick.com/forum/156125/can-you-explain-the-difference-between-organic-and-paid-results) between `StreamReader` and `File.ReadAllLines()`.

## Replies

### Reply by Anubhav Sharma

The [difference](https://www.mindstick.com/articles/157114/good-news-or-bad-news-and-the-difference-is) between `StreamReader` and `File.ReadAllLines()` in C# lies mainly in **how they read the file** and **when you would use each**.

### `File.ReadAllLines(string path)`

1. Reads **all lines of a text file** at once.
2. Returns a `string[]` (array of strings).
3. File is **opened, read, and closed** automatically.
4. Not suitable for **very large files** (can use a lot of memory).

## Example:

```cs
string[] lines = File.ReadAllLines("example.txt");
foreach (string line in lines)
{
    Console.WriteLine(line);
}
```

### `StreamReader`

1. Reads a file **line-by-line** or **character-by-character**.
2. Gives **more control** over reading (e.g., read a specific number of lines, skip lines, read partial content).
3. Better for **large files** or **streamed reading**.
4. You **manually control** the reading process and resource disposal (usually with `using`).

## Example:

```cs
using (StreamReader reader = new StreamReader("example.txt"))
{
    string line;
    while ((line = reader.ReadLine()) != null)
    {
        Console.WriteLine(line);
    }
}
```

### Summary of Differences

| Feature | `File.ReadAllLines()` | `StreamReader` |
| --- | --- | --- |
| Reads entire file | Yes | No (line-by-line or custom reading) |
| Returns | `string[]` | Each line via `ReadLine()` |
| Memory usage | High (if file is large) | Low (reads as needed) |
| Suitable for large files | No | Yes |
| Custom read logic | No | Yes |
| Ease of use | Simple | Requires more control |

### When to Use Which?

1. Use `File.ReadAllLines()` for **small to medium files** when you want all lines immediately.
2. Use `StreamReader` for **large files** or when you need **streamed/customized reading** logic.


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Original Source: https://www.mindstick.com/forum/161576/explain-the-difference-between-streamreader-and-file-readalllines

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