How can I String.Format a TimeSpan object with a custom format in .NET?

Question

What is the recommended way of formatting TimeSpan objects into a string with a custom format?

Answer 1

If you want the duration format similar to youtube, given the number of seconds

int[] duration = { 0, 4, 40, 59, 60, 61, 400, 4000, 40000, 400000 };
foreach (int d in duration)
{
    Console.WriteLine("{0, 6} -> {1, 10}", d, d > 59 ? TimeSpan.FromSeconds(d).ToString().TrimStart("00:".ToCharArray()) : string.Format("0:{0:00}", d));
}

Output:

     0 ->       0:00
     4 ->       0:04
    40 ->       0:40
    59 ->       0:59
    60 ->       1:00
    61 ->       1:01
   400 ->       6:40
  4000 ->    1:06:40
 40000 ->   11:06:40
400000 -> 4.15:06:40