Question

Ok,

I have a string in a sql table like this

hello /r/n this is a test /r/n new line. 

When i retrieve this string using c# for a textbox using multiline i expect the escape chars to be newlines.

But they are not and what happens is i get the line exactly as it is above.

It seems that the string returned from the table is taken as literal but i want the newlines!

How do i get this to work?

Thanks in advance..

Answer 1

Things like ‘\n’ (not ‘/n’ by the way) are escape characters in programming languages, not inherently in text. (In particular, they’re programming-language dependent.)

If you want to make

hello\r\nthis is a test\r\nnew line 

format as

hello this is a test new line 

you’ll need to do the parsing yourself, replacing ‘\r’ with carriage return, ‘\n’ with newline etc, handling ‘\’ as a literal backslash etc. I’ve typically found that a simple parser which just remembers whether or not the previous character was a backslash is good enough for most purposes. Something like this:

static string Unescape(string text) {     StringBuilder builder = new StringBuilder(text.Length);     bool escaping = false;     foreach (char c in text)     {         if (escaping)         {            // We're not handling \uxxxx etc            escaping = false;            switch(c)            {                case 'r': builder.Append('\r'); break;                case 'n': builder.Append('\n'); break;                case 't': builder.Append('\t'); break;                case '\\': builder.Append('\\'); break;                default:                    throw new ArgumentException('Unhandled escape: ' + c);            }         }         else         {            if (c == '\\')            {                escaping = true;            }            else            {                builder.Append(c);            }         }     }     if (escaping)     {         throw new ArgumentException('Unterminated escape sequence');     }     return builder.ToString(); } 

There are more efficient ways of doing it (skipping from backslash to backslash and appending whole substrings of non-escaped text, basically) but this is simple.