How do you handle encoding when reading or writing to text files?

Question

ICSM Computer · Answer

Handling encoding correctly when reading or writing text files in .NET is critical for ensuring data integrity, especially with non-ASCII characters or cross-platform compatibility.
✅ Key Points on Handling Encoding
1. Specify Encoding Explicitly
Always specify the encoding when reading or writing, unless you're sure the default (UTF-8 without BOM) works for your scenario.
Writing Text with Encoding
Using File.WriteAllText:
string text = "Hello, world — 你好，世界";
File.WriteAllText("file.txt", text, Encoding.UTF8); // or Encoding.Unicode, etc.
Using StreamWriter:
using (var writer = new StreamWriter("file.txt", false, Encoding.UTF8))
{
    writer.WriteLine("Some text");
}
Common Encodings:
Encoding.UTF8 – Universal, default for many appsEncoding.Unicode – UTF-16 LEEncoding.ASCII – 7-bit ASCII only (loses non-ASCII characters)Encoding.GetEncoding("ISO-8859-1") – Western European (legacy)new UTF8Encoding(encoderShouldEmitUTF8Identifier: true) – With BOM
Reading Text with Encoding
Using File.ReadAllText:
string content = File.ReadAllText("file.txt", Encoding.UTF8);
Using StreamReader:
using (var reader = new StreamReader("file.txt", Encoding.UTF8))
{
    string content = reader.ReadToEnd();
}
Detecting Encoding Automatically (BOM-based):
using (var reader = new StreamReader("file.txt", detectEncodingFromByteOrderMarks: true))
{
    string content = reader.ReadToEnd();
}
If you're unsure about the encoding, setting detectEncodingFromByteOrderMarks: true can help detect UTF-8/UTF-16 with BOM.
Example: Writing and Reading Unicode Text
string text = "Text with emoji and Chinese 中文";
// Write with UTF-8
File.WriteAllText("unicode.txt", text, Encoding.UTF8);
// Read it back
string readBack = File.ReadAllText("unicode.txt", Encoding.UTF8);
Common Mistakes
Mistake
Problem
Not specifying encoding
May cause unreadable characters on other systems or in other programs
Using Encoding.ASCII for Unicode text
Non-ASCII characters get lost or replaced
Writing UTF-8 text without BOM when BOM is expected (e.g., in Notepad)
File may appear garbled or empty
Reading UTF-16 with UTF-8
Results in mojibake (garbled text)

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How do you handle encoding when reading or writing to text files?

ICSM Computer

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1 Answers

✅ Key Points on Handling Encoding

1. Specify Encoding Explicitly

Writing Text with Encoding

Using `File.WriteAllText`:

Using `StreamWriter`:

Common Encodings:

Reading Text with Encoding

Using `File.ReadAllText`:

Using `StreamReader`:

Detecting Encoding Automatically (BOM-based):

Example: Writing and Reading Unicode Text

Common Mistakes

Liked By

Mistake	Problem
Not specifying encoding	May cause unreadable characters on other systems or in other programs
Using `Encoding.ASCII` for Unicode text	Non-ASCII characters get lost or replaced
Writing UTF-8 text without BOM when BOM is expected (e.g., in Notepad)	File may appear garbled or empty
Reading UTF-16 with UTF-8	Results in mojibake (garbled text)