C# + Format TimeSpan

Question

I am trying to format a TimeSpan element in the format of \"[minutes]:[seconds]\". In this format, 2 minutes and 8 seconds would look like \"02:08\". I have tried a variety

Answer 1

NOTE: This answer applies to .NET 4.0 only.

The colon character is a literal and needs to be wrapped in single quotes:

duration.ToString("mm':'ss")

From the MSDN documentation:

The custom TimeSpan format specifiers do not include placeholder separator symbols, such as the symbols that separate days from hours, hours from minutes, or seconds from fractional seconds. Instead, these symbols must be included in the custom format string as string literals.