c# - How does Encoding.Default work in .NET?

Question

I'm reading a file using:

var source = File.ReadAllText(path);

and the character ? wasn't being loaded correctly.

Then, I changed it to:

var source = File.ReadAllText(path, Encoding.UTF8);

and nothing.

I decided to try using

var source = File.ReadAllText(path, Encoding.Default);

and it worked perfectly. Then I debugged it and tried to find which Encoding did the trick, and I found that it was UTF-7.

What I want to know is:

Is it recommended to use Encoding.Default, and can it guarantee all the characters of the file will be read without problems?

Answer 1

It is not recommended to use Encoding.Default.

Quote from MSDN:

Different computers can use different encodings as the default, and the default encoding can even change on a single computer. Therefore, data streamed from one computer to another or even retrieved at different times on the same computer might be translated incorrectly. In addition, the encoding returned by the Default property uses best-fit fallback to map unsupported characters to characters supported by the code page. For these two reasons, using the default encoding is generally not recommended. To ensure that encoded bytes are decoded properly, your application should use a Unicode encoding, such as UTF8Encoding or UnicodeEncoding, with a preamble. Another option is to use a higher-level protocol to ensure that the same format is used for encoding and decoding.