/* solution 1*/
static string Escape1(string source, char[] escapeChars, char escape) {
  int i = source.IndexOfAny(escapeChars);
  while (i != -1) {
    source = source.Insert(i, escape.ToString());
    i = source.IndexOfAny(escapeChars, i + 2);
  }
  return source.ToString();
}

/* solution 2*/
static string Escape2(string source, char[] escapeChars, char escape) {
  StringBuilder s = new StringBuilder();
  int j = 0;
  int i = source.IndexOfAny(escapeChars);
  while (i != -1) {
    s.Append(source.Substring(j, i - j));
    s.Append(escape);
    j = i;
    i = source.IndexOfAny(escapeChars, j + 1);
  }
  s.Append(source.Substring(j));
  return s.ToString();
}

http://www.codeproject.com/KB/string/string_optimizations.aspx

Another common task when working with strings is to replace a set of characters with a set of escape sequences. Sometimes the replacement is very easy - you only have to place a backslash (or another character) before every occurrence of an escaped character.

Imagine the following scenario: you are building an RTF file and you want to insert a string into the file. The "{", "}", and "\" characters have a special meaning in RTF and, therefore, must be preceded with a backslash. The question is: what is the fastest way to replace each of the characters with a corresponding escape sequence?

Replacing characters with escape sequences

c

C#