Strange Behavior When Writing a String to a UTF-8 File (No BOM) - The ANSI File Is Returned


I'm attempting to write out C# string data to a UTF-8 file without a byte order mark (BOM), but am getting an ANSI file created.

using (StreamWriter objStreamWriter = new StreamWriter(SomePath, false, new UTF8Encoding(false)))
objStreamWriter.Write("Hello world - Encoding no BOM but actually returns ANSI");

According to the documentation for the UTF8Encoding class constructor, setting the encoderShouldEmitUTF8Identifier parameter to false should inhibit the Byte Order Mark.

I'm using .NET Framework 4.5 on my British (en-gb) computer. Below is screenshot of the ScreenWriter object showing UTF8Encoding in place.

So why am I getting an ANSI file (as checked with Notepad++) back from this operation?

Your example string that you're writing to the file consists only of characters in the ASCII range. The ASCII range is shared by ASCII, UTF-8 and most (all?) ANSI code pages. So, given that there is no BOM, Notepad++ has no indication if UTF-8 or ANSI is meant, and apparently defaults to ANSI.