C# ByteArray to string conversion and back

Question

I have a uint value that I need to represent as a ByteArray and the convert in a string. When I convert back the string to a byte array I found different values. I'm using standard ASCII converter so I don't understand why I'm getting different values. To be more clear this is what I'm doing:

byte[] bArray = BitConverter.GetBytes((uint)49694);
string test = System.Text.Encoding.ASCII.GetString(bArray);
byte[] result = Encoding.ASCII.GetBytes(test);

The bytearray result is different from the first one:

bArray ->

[0x00000000]: 0x1e
[0x00000001]: 0xc2
[0x00000002]: 0x00
[0x00000003]: 0x00

result ->

[0x00000000]: 0x1e
[0x00000001]: 0x3f
[0x00000002]: 0x00
[0x00000003]: 0x00

Notice that the byte 1 is different in the two arrays.

Thanks for your support.

Regards

Answer 1

string test = System.Text.Encoding.ASCII.GetString(bArray);
byte[] result = Encoding.ASCII.GetBytes(test);

Because raw data is not ASCII. Encoding.GetString is only meaningful if the data you are decoding is text data in that encoding. Anything else: you corrupt it. If you want to store a byte[] as a string, then base-n is necessary - typically base-64 because a: it is conveniently available (Convert.{To|From}Base64String), and b: you can fit it into ASCII, so you rarely hit code-page / encoding issues. For example:

byte[] bArray = BitConverter.GetBytes((uint)49694);
string test = Convert.ToBase64String(bArray); // "HsIAAA=="
byte[] result = Convert.FromBase64String(test);

Answer 2

Because c2 is not a valid ASCII char and it is replaced with '?'(3f)

Converting any byte array to string using SomeEncoding.GetString() is not a safe method as @activwerx suggested in comments. Instead use Convert.FromBase64String, Convert.ToBase64String