Finding the string length of a integer in .NET

Question

In .NET what is the best way to find the length of an integer in characters if it was represented as a string?

e.g.

1 = 1 character
10 = 2 characters

Answer 1

If input is in range 0-10000

if (i < 10) return 1;
if (i < 100) return 2;
if (i < 1000) return 3;
if (i < 10000) return 4;
// etc