A few days ago I blogged Optional parameters considered harmful; well, as is often the case – I was missing a trick. Maybe they aren’t as bad as I said. Patrick Huizinga put me right; I don’t mind admitting: I was being stupid.
To recap, we had a scenario were these two methods were causing a problem:
static void Compute(int value, double factor = 1.0,
string caption = null)
{ Compute(value, factor, caption, null); }
static void Compute(int value, double factor = 1.0,
string caption = null, Uri target = null)
{ /* ... */ }
What I should have done is: make the parameters non-optional in all overloads except the new one. Existing compiled code isn’t interested in the optional parameters, so will still use the old methods. New code will use the most appropriate overload, which will often (but not quite always) be the overload with the most parameters – the optional parameters.
static void Compute(int value, double factor,
string caption)
{ Compute(value, factor, caption, null); }
static void Compute(int value, double factor = 1.0,
string caption = null, Uri target = null)
{ /* ... */ }
There we go; done; simple; working; no issues. My thanks to Patrick for keeping me honest.
