title: How can I validate mobile number using Regex in C#
body: <p>Recently I'm working in a project, in which I need validate some mobile numbers according to mobile operator's codes. Here some examples:</p>
  
  <blockquote>
    <p>01100000000<br>
    01500000000<br>
    01700000000<br>
    01800000000<br>
    01900000000</p>
  </blockquote>
  
  <p>Now I want to validate, first 3 digits must be in (011,015,017,018,019) and next 8 characters must be digit and if user enter something like 0120000000 then the match will be false, cause
  valid operator code should be in (011,015,017,018,019).</p>