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Possible Duplicate:
Encode to single byte extended ascii values

In C#, I'm trying to replace substrings in a string with non-printing characters (characters with byte codes above 0xE0). I've seen many questions that are going the other way -- i.e. trying to remove non-printing characters from a string -- but not trying to insert non-printing characters. The code below (which doesn't work correctly) is where I am now:

string[] _symbol = {"Hello", "the", "man"};
string _source = "\"Hello, Hello,\" the man said.\n\"Hello,\" the woman replied.";
string _expect = "\"\xF3, \xF3,\" \xF2 \xF1 said.\n\"\xF3,\" \xF2 wo\xF1 replied.";

byte[] tblix = { 0xF3, 0x00 };
string _repl, _dest;

_repl = System.Text.Encoding.UTF8.GetString(tblix, 0, 1);
_dest = _source.Replace(_symbol[0], _repl);

tblix[0]--;
_repl = System.Text.Encoding.UTF8.GetString(tblix, 0, 1);
_dest = _dest.Replace(_symbol[1], _repl);

tblix[0]--;
_repl = System.Text.Encoding.UTF8.GetString(tblix, 0, 1);
_dest = _dest.Replace(_symbol[2], _repl);

bool check = (_dest == _expect);

File.WriteAllText("temp.dat", _dest);

I am expecting to produce a string in _dest that is equivalent to _expect; If I use ASCII encoding, the non-printing characters revert to '?'. UTF8 doesn't work correctly either. Moreover, I want the output to be written to the file as a sequence of single-byte characters, so converting everything to a multibyte encoding would eventually require coming back to a single-byte representation. Is there a convenient way to do what I'm trying to accomplish? Thanks in advance for any suggestions.

Community
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laser_dude
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  • It looks like you have an [XY Problem](http://meta.stackexchange.com/questions/66377/what-is-the-xy-problem), that is, you have a solution that isn't working but we don't know why it isn't working because we don't know your end goal. – Erik Philips Oct 26 '12 at 19:48
  • My goal is to produce a file in which each character (including non-printing ones) is represented by one byte, and when I open the file, I should see exactly what is shown in the _expect variable. However, using UTF8 representation in the Replace results in multibyte non-printing characters, and using ASCII representation turns all characters above \127 into '?'. – laser_dude Oct 26 '12 at 20:34

2 Answers2

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Create the char directly, not from encoding...

        string file = @"C:\Temp\temp.dat";

        string[] _symbol = { "Hello", "the", "man" };
        string _source = "\"Hello, Hello,\" the man said.\n\"Hello,\" the woman replied.";
        string _expect = "\"\xF3, \xF3,\" \xF2 \xF1 said.\n\"\xF3,\" \xF2 wo\xF1 replied.";

        //byte[] tblix = { 0xF3, 0x00 };

        char c = (char)0xF300;

        string _repl, _dest;

        //_repl = System.Text.Encoding.UTF8.GetString(tblix, 0, 1);
        _dest = _source.Replace(_symbol[0], c.ToString());

        c -= (char)0x100;
        //_repl = System.Text.Encoding.UTF8.GetString(tblix, 0, 1);
        _dest = _dest.Replace(_symbol[1], c.ToString());

        c -= (char)0x100;
        //_repl = System.Text.Encoding.UTF8.GetString(tblix, 0, 1);
        _dest = _dest.Replace(_symbol[2], c.ToString());

        bool check = (_dest == _expect);

        File.WriteAllText(file, _dest);

I believe that is is trying to convert to a printable character, whereas, creating the char directly forces that exact char to print (or not in this case). This is a copy of the code that I copied from you and put into a new Console app. Did exactly as you said, and I made these changes and then it worked.

iMortalitySX
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  • This is indeed much more straightforward and elegant. The issue that I see with this is that when I look at the file, the non-printing characters are still in multibyte (UTF8) format, but I would like them to occupy only a single byte each. – laser_dude Oct 26 '12 at 20:16
  • @laser_dude Sorry, I actually didn't realize that your goal was for EVERY char to be single byte! – iMortalitySX Oct 26 '12 at 21:07
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I was able to get this to work using a Windows-1252 encoding, as in the modified code below. I also had to ensure that the file was being written in 1252 encoding, as well.

string file = @"C:\Temp\temp.dat";

string[] _symbol = { "Hello", "the", "man" };
string _source = "\"Hello, Hello,\" the man said.\n\"Hello,\" the woman replied.";
string _expect = "\"\xF3, \xF3,\" \xF2 \xF1 said.\n\"\xF3,\" \xF2 wo\xF1 replied.";
byte[] tblix = { 0xF3 };

string _repl, _dest;

Encoding e1252 = Encoding.GetEncoding(1252);
_repl = e1252.GetString(tblix);
_dest = _source.Replace(_symbol[0], _repl);

tblix[0]--;
_repl = e1252.GetString(tblix);
_dest = _dest.Replace(_symbol[1], _repl);

tblix[0]--;
_repl = e1252.GetString(tblix);
_dest = _dest.Replace(_symbol[2], _repl);

bool check = (_dest == _expect);

TextWriter tw = new StreamWriter(file, false, e1252);
tw.Write(_dest);
tw.Close();
laser_dude
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