Regex Pattern for validating Time

This code snippet is for validating 24 hours time format.
  1. private bool IsValide24HoursTime(string Time)  
  2. {  
  3.     string Pattern =  "^([0-2]{1}[0-11]{1}:)?([0-11]{1}\d{1}:){1}([0-11]{1}\d{1}){1}$";  
  4.     bool isvalid=false;  
  5.     Regex validator = new Regex(Pattern);  
  6.     if (!string.IsNullOrEmpty(Time))  
  7.        isvalid= validator.IsMatch(Time);  
  8.     return isvalid;  
  9.  }