How to use default parameters in C#?

Question

In other languages I can set up the method signature like

cookEgg(boolean hardBoiled = true)

This defaults the parameter hardboiled to true, if I don't receive a parameter in the method call.

How would I achieve this in C#?

Solution 1

At present, you have to overload the method:

void cookEgg(bool hardBoiled) { ... }
void cookEgg() { cookEgg(true); }

C# 4.0 will add optional arguments - you will be able to write code exactly as in your original sample, and it will work as you'd expect.

Solution 2

Default parameters are supported in C# 4 (Visual Studio 2010).

http://msdn.microsoft.com/en-us/library/dd264739(VS.100).aspx

Solution 3

This is not what you look exactly but I think params argument is another answer.

void test(params int []arg) { }

Comments

[Zack]

I'm looking forward to this feature tbh. Rather annoying to have to make an overloaded method to have this feature at the moment. I'm also hoping for static extension methods (extending a static class, like... System.String or something).

[Pavel Minaev]

I must be missing something, as you can easily define extension methods for System.String in C# 3.0.