title: C# regex to remove non - printable characters, and control characters, in a text that has a mix of many different languages, unicode letters
body: <p>i would appreciate your help on this, since i do not know which range of characters to use, or if there is a character class like [[:cntrl:]] that i have found in ruby?</p>
  
  <p>by means of non printable, i mean delete all characters that are not shown in ie output, when one prints the input string. Please note, i look for a c# regex, i do not have a problem with my code</p>