How unescape RFC 3986 string

Question

I've a RFC 3986 encoded string in the form %x##. For example the space character is encoded as %x20 instead of %20. How can I decode it in C#? Using the decode method of Uri, HttpUtility or WebUtility classes the string was not decoded.

Answer 1

You can try regular expressions in order to Replace all %x## as well as %## matches:

  using System.Text.RegularExpressions;

  ...

  string demo = "abc%x20def%20pqr";

  string result = Regex.Replace(
      demo, 
    "%x?([0-9A-F]{2})", 
      m => ((char)Convert.ToInt32(m.Groups[1].Value, 16)).ToString(), 
      RegexOptions.IgnoreCase);

  Console.Write(result);

Outcome:

  abc def pqr