How to add characters to a string in C#

Question

Problem: I would like add characters to a phone.

So instead of displaying ###-###-####, I would like to display (###) ###-####.

I tried the foll

Answer 1

It's worth noting that strings are immutable in C#.. meaning that if you attempt to modify one you'll always be given a new string object.

One route would be to convert to a number (as a sanity check) then format the string

var result = String.Format("{0:(###) ###-####}", double.Parse("8005551234"))

If you'd rather not do the double-conversion then you could do something like this:

var result = String.Format("({0}) {1}-{2}", x.Substring(0 , 3), x.Substring(3, 3), x.Substring(6));

Or, if you already have the hyphen in place and really just want to jam in the parenthesis then you can do something like this:

var result = x.Insert(3, ")").Insert(0, "(");