String.Format Phone Numbers with Extension

c#, string

Solution

I think you'll have to break your phoneDigits string into the first 10 digits and the remainder.

//[snip]
else if (phoneDigits.ToString().Length > 10)
        {
            return String.Format("{0:(###) ###-#### x}{1}", phoneDigits.Substring(0,10), phoneDigits.Substring(10) );
        }
//[snip]

Problem

I am trying to create a an function that formats US phone numbers -- hopefully without looping through each digit. When 10 digits are passed in all is fine. How ever when more than 10 digits are passed in I want the String.Format method to append the extension digits on the right. For example: When 14 digits passed in the result should be:(444)555-2222 x8888 When 12 digits passed in the result should be:(444)555-2222 x88 etc. However what I get with my current attempt is: Passing in 12 digits returns this string '() -949 x555444433' here is what I have so far. ``` public static string _FormatPhone(object phonevalue) { Int64 phoneDigits; if (Int64.TryParse(phonevalue.ToString(), out phoneDigits)) { string cleanPhoneDigits = phoneDigits.ToString(); int digitCount = cleanPhoneDigits.Length; if (digitCount == 10) return String.Format("{0:(###) ###-####}", phoneDigits); else if (digitCount > 10) return String.Format("{0:(###) ###-#### x#########}", phoneDigits); else return cleanPhoneDigits; } return "Format Err#"; } ``` Thanks in advance.

Original source