Home » c# » Passing an empty array as default value of an optional parameter [duplicate]

Passing an empty array as default value of an optional parameter [duplicate]

Posted by: admin November 30, 2017 Leave a comment

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This question already has an answer here:

Answers:

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];

Questions:
Answers:

If you can make the array the last argument you could also do this:

public void DoSomething(int index, bool wasThirdParam = true, params ushort[] array)

The compiler will automatically pass an empty array if it is not specified, and you get the added flexibility to either pass an array as a single argument or put the elements directly as variable length arguments to your method.

Questions:
Answers:

I know it’s an old question, and whilst this answer doesn’t directly solve how to get around the limitations imposed by the compiler, method overloading is an alternative:

   public void DoSomething(int index, bool thirdParam = true){
        DoSomething(index, new ushort[] {}, thirdParam);
   }

   public void DoSomething(int index, ushort[] array, bool thirdParam = true){

      ...
   }