How can you use optional parameters in C#?


Question

Note: This question was asked at a time when C# did not yet support optional parameters (i.e. before C# 4).

We're building a web API that's programmatically generated from a C# class. The class has method GetFooBar(int a, int b) and the API has a method GetFooBar taking query params like &a=foo &b=bar.

The classes needs to support optional parameters, which isn't supported in C# the language. What's the best approach?

1
443
3/20/2017 5:38:25 PM

Accepted Answer

Surprised no one mentioned C# 4.0 optional parameters that work like this:

public void SomeMethod(int a, int b = 0)
{
   //some code
}

Edit: I know that at the time the question was asked, C# 4.0 didn't exist. But this question still ranks #1 in Google for "C# optional arguments" so I thought - this answer worth being here. Sorry.

975
1/7/2011 3:17:22 PM

Another option is to use the params keyword

public void DoSomething(params object[] theObjects)
{
  foreach(object o in theObjects)
  {
    // Something with the Objects…
  }
}

Called like...

DoSomething(this, that, theOther);

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