Question

In VB.NET, which is better to use: function overloading or default parameters?

Answer 1

Is the code going to be used by other languages? If so, that swings the balance towards overloads while still bearing Hamish’s answer in mind. In particular, C# doesn’t support optional parameters – yet…

Admittedly this wouldn’t actually prevent someone using your code from C#, it just might be a pain for them.

If there are a lot of parameters and they logically represent something, you might want to consider encapsulating them together, in the same way that Process works with ProcessStartInfo. That’s particularly nice from C# due to object initializers.

If this is for construction, you might also consider the builder pattern as a variant of this. For instance, in Protocol Buffers I can do something like:

Person jon = new Person.Builder { Name='Jon', Age=32,                                   Spouse='Holly', Kids=3 }.Build(); 

which ends up being very readable while still creating a person in one go (in one expression, and without having to mutate the person itself – indeed the message type is immutable; it’s only the builder which isn’t).