Verify a specific phone number RRS feed

  • Question

  • how to write C# code  method will verify phone numbers in accordance with the North American Numbering Plan (NANP) rules.
    Friday, May 11, 2018 12:42 PM

All replies

  • Have you tried a 3rd party library search using Bing or Google or maybe an open source library search.

    Surely, there is source code or a library that already has the functionality out there if you look.

    Saturday, May 12, 2018 7:46 AM
  • Hi Hakimeh,

    For your requirement, you could try "Regex", and I suggest you try code below:

    string userInput = txtPhoneNumber.Text;
    Regex regexPhoneNumber = new Regex(@"^\(?([0-9]{3})\)?[-. ]?([0-9]{3})[-. ]?([0-9]{4})$");
    if (regexPhoneNumber.IsMatch(userInput))
        string formattedPhoneNumber = regexPhoneNumber.Replace(userInput, "($1) $2-$3");
        // Invalid phone number

    Best Regards,

    Tao Zhou

    MSDN Community Support
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    Monday, May 14, 2018 3:29 AM
  • All you have to do is search using Bing or Google.


    The function provided below validates a telephone against the requirements of the North American Number Plan (NANP) as administered by Neustar, Inc.


    Yeah, I wrote programs for Cincinnati Bell. :) 

    Monday, May 14, 2018 3:59 PM