formatting string in MVC /C#

Question

I have a string 731478718861993983 and I want to get this 73-1478-7188-6199-3983 using C#. How can I format it like this ?

Thanks.

Answer 1

Here's how I'd do it; it'll only work if you're storing the numbers as something which isn't a string as they're not able to be used with format strings.

string numbers = "731478718861993983";
string formattedNumbers = String.Format("{0:##-####-####-####-####}", long.Parse(numbers));

Edit: amended code, since you said they were held as a string in your your original question