How to cascade optional parameter?

Question

I have a worker method with an optional parameter

Work(string input = DefaultInput)
{
    //do stuff
}

And I have a wrapper around this, which also take the string input, but this can also be optional...

WorkWrapper(int someParameter, string input = DefaultInput)
{
    //do initialization
    Work(input);

}

The problem here is I duplicate reference to DefaultInput, if, say, I change the default input of work to NewDefaultInput, I will need to update the workWrapper as well, otherwise it will still use the old default.

Is there a way so that the default input do not need to be declared twice? Possibly without having two overloads for workwrapper..

Answer 1

If you want the defaults to be in sync between the two methods, you really don't need the default in the wrapper, right?

public void Work(string input = DefaultInput)
{
    //do stuff
}

…

public void WorkWrapper(int someParameter, string inputOverride = null)
{
    //do initialization

    if (inputOverride == null) Work();
    else Work(inputOverride);    
}

---

If they are in the same class/hierarchy, you could also just declare a const to ensure that the defaults remain the same.

private const string DEFAULT_INPUT = "Default Input"; // protected if in base class

public void Work(string input = DEFAULT_INPUT)
{
    //do stuff
}

public void WorkWrapper(int someParameter, string input = DEFAULT_INPUT)
{
    //do initialization
    Work(input);    
}