C# 4.0: Can I use a TimeSpan as an optional parameter with a default value?

Question

Both of these generate an error saying they must be a compile-time constant:

void Foo(TimeSpan span = TimeSpan.FromSeconds(2.0))
void Foo(TimeSpan span = new         


        

Answer 1

TimeSpan is a special case for the DefaultValueAttribute and is specified using any string that can be parsed via the TimeSpan.Parse method.

[DefaultValue("0:10:0")]
public TimeSpan Duration { get; set; }