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 (timeSpan.TotalDays < 1)
    return timeSpan.ToString(@"hh\:mm\:ss");

return timeSpan.TotalDays < 2
    ? timeSpan.ToString(@"d\ \d\a\y\ hh\:mm\:ss")
    : timeSpan.ToString(@"d\ \d\a\y\s\ hh\:mm\:ss");

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