c# and Encoding.ASCII.GetString

Question

byte[] header = new byte[]{255, 216}; 

string ascii =  Encoding.ASCII.GetString(header);

I expect ASCII to be equal to be FFD8 (JPEG SOI marker)

Instead I get "????"

Answer 1

In this case you'd be better to compare the byte arrays rather than converting to string.

If you must convert to string, I suggest using the encoding Latin-1 aka ISO-8859-1 aka Code Page 28591 encoding, as this encoding will map all bytes with hex values are in the range 0-255 to the Unicode character with the same hex value - convenient for this scenario. Any of the following will get this encoding:

Encoding.GetEncoding(28591)
Encoding.GetEncoding("Latin1")
Encoding.GetEncoding("ISO-8859-1")