Convert a Unicode string to an escaped ASCII string

Question

How can I convert this string:

This string contains the Unicode character Pi(π)

into an escaped A

Answer 1

string StringFold(string input, Func proc)
{
  return string.Concat(input.Select(proc).ToArray());
}

string FoldProc(char input)
{
  if (input >= 128)
  {
    return string.Format(@"\u{0:x4}", (int)input);
  }
  return input.ToString();
}

string EscapeToAscii(string input)
{
  return StringFold(input, FoldProc);
}