I’ve run into this as well and the only workaround I’ve found is to use nullables. public void log(String msg, Color? c = null) { loggerText.ForeColor = c ?? Color.Black; loggerText.AppendText(“\n” + msg); } Other possible syntax is: loggerText.ForeColor = c.GetValueOrDefault(Color.Black);
You have to specify the default values for the arguments only in the declaration but not in the definition. class pBase : public sf::Thread { // …. void setColor( int _color = -1 ); // …. } ; void pBase:: setColor( int _color ) { // …. } The default value for an member function’s … Read more
What is really strange is that the value you put for the optional parameter in the interface actually makes a difference. I suppose you have to question whether the value is an interface detail or an implementation detail. I would have said the latter but things behave like the former. The following code outputs 1 … Read more
You can disambiguate by calling: this.MyMethod(); (in MyMethod2()) Whether it is a bug is tricky; it does look inconsistent, though. ReSharper warns you simply not to have changes to the default value in an override, if that helps ;p Of course, ReSharper also tells you the this. is redundant, and offers to remove it for … Read more
This uses jQuery.extend but could be interchanged with an object merger from your library of choice or Object.assign in ES6. function Module(options){ var defaults = { color: ‘red’ }; var actual = $.extend({}, defaults, options || {}); console.info( actual.color ); } var a = new Module(); // Red var b = new Module( { color: … Read more
As of the C# 2.0 compiler, there is very little point to String.Empty anyway, and in fact in many cases it’s a pessimisation, since the compiler can inline some references to “” but can’t do the same with String.Empty. In C# 1.1 it was useful to avoid creating lots of independent objects all containing the … Read more
I’d consider the following: Do you need your code to be used from languages which don’t support optional parameters? If so, consider including the overloads. Do you have any members on your team who violently oppose optional parameters? (Sometimes it’s easier to live with a decision you don’t like than to argue the case.) Are … Read more
You can’t create compile-time constants of object references. The only valid compile-time constant you can use is null, so change your code to this: public void DoSomething(int index, ushort[] array = null, bool thirdParam = true) And inside your method do this: array = array ?? new ushort[0]; (from comments) From C# 8 onwards you … Read more
You should enclose the optional closure in parentheses. This will properly scope the ? operator. func then(onFulfilled: ()->(), onReject: (()->())?){ if let callableRjector = onReject { // do stuff! } }
There is a workaround for this, taking advantage of nullable types and the fact that null is a compile-time constant. (It’s a bit of a hack though, and I’d suggest avoiding it unless you really can’t.) public void SomeClassInit(Guid docId, DateTime? addedOn = null) { if (!addedOn.HasValue) addedOn = DateTime.Now; //Init codes here } In … Read more