Question

11. Write the correct regular expression pattern for a phone number field with the format XXX-XXX-XXXX

Answer 1

PROC TELEPHONE_NUMBER

postproc

  if regexmatch(TELEPHONE_NUMBER, "^([0-9]{3}-){2}[0-9]{4}$") = 0 then
  errmsg("Invalid format! Use the following format: xxx-xxx-xxxx.");
  reenter;
  endif;

OR

<asp:regularexpressionvalidator validationexpression="”\d{3}-\d{3}-\d{4}”ControlToValidate=”txtPhone”" id="”RegExpVal_txtPhone”" runat="”server”" errormessage="”Invalid" format="" (="" use:="" xxx-xxx-xxxx)”="" display="”Dynamic”"></asp:regularexpressionvalidator>

code in action, run the example

protected bool IsValidPhone(string strPhoneInput)
{
   // Remove anything that is not a number
   string strPhone = Regex.Replace(strPhoneInput, @"[^\d]", String.Empty);

   txtPhone2.Text = strPhone;

   // Check for exactly 10 numbers left over
   return (strPhone.Length == 10);
}