is there a bug in TimeSpan

Question

TimeSpan span = TimeSpan.Zero;
span.Add(TimeSpan.FromMinutes(5));
Console.WriteLine(span.TotalSeconds);   -----> will out put "0"

however

TimeSpan span = TimeSpan.Zero.Add(TimeSpan.FromMinutes(5));
Console.WriteLine(span.TotalSeconds);   -----> will out put "300"

Does anyone see this before???

Answer 1

TimeSpan is a struct. TimeSpan.Add does not modify the input - it returns a new TimeSpan which is the input plus the addend:

Remarks

The return value must be between TimeSpan.MinValue and TimeSpan.MaxValue; otherwise, an exception is thrown.

The return value is a new TimeSpan; the original TimeSpan is not modified.

Answer 2

Not a bug in Timespan but.... in the way structures get copied in C#.