How to validate a (country specific) phone number

Question

A valid phone number contains:

• Less than 9 characters
• A "+" at the start
• Only digits.

I\'m trying to use regular expre

Answer 1

Expanding upon one of the answers provided above, the method I came up with to also handle a few phone number delivery styles as well as international phone number is

    internal static bool IsValidPhoneNumber(this string This)
    {
        var phoneNumber = This.Trim()
            .Replace(" ", "")
            .Replace("-", "")
            .Replace("(", "")
            .Replace(")", "");
        return Regex.Match(phoneNumber, @"^\+\d{5,15}$").Success;
    }