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

For .NET 3.5 and lower you could use:

string.Format ("{0:00}:{1:00}:{2:00}", 
               (int)myTimeSpan.TotalHours, 
                    myTimeSpan.Minutes, 
                    myTimeSpan.Seconds);

Code taken from a Jon Skeet answer on bytes

For .NET 4.0 and above, see DoctaJonez answer.