C# – Calling Overridden Constructor and Base Constructor in C#

cconstructor

I have two classes, Foo and Bar, that have constructors like this:

class Foo
{
    Foo()
    {
      // do some stuff
    }

    Foo(int arg)
    {
      // do some other stuff
    }
}

class Bar : Foo
{
    Bar() : base()
    {
      // some third thing
    }
}

Now I want to introduce a constructor for Bar that takes an int, but I want the stuff that happens in Bar() to run as well as the stuff from Foo(int). Something like this:

Bar(int arg) : Bar(), base(arg)
{
  // some fourth thing
}

Is there any way to do this in C#? The best I have so far is putting the work done by Bar() into a function, that also gets called by Bar(int), but this is pretty inelegant.

Best Answer

I would re-chain constructors, so they are called like 

Bar() : this(0) 
Bar(int) : Foo(int) initializes Bar
Foo(int) initializes Foo
Foo() : this(0)

This is suitable, if parameterless constructors are assuming some kind of default value for int parameter of other constructor. If constructors are unrelated, you probably doing something wrong with your type, or maybe we need more information about what are you trying to achieve.

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