Passing parameters to the base class constructor

Question

If the base class and derived class both have their constructors with parameters then where we pass the parameters to the base class constructors?

Solution

Like this:

public class DerivedClass : BaseClass
{
    public DerivedClass(int derivedParam, String baseParam):base(baseParam)
    {
    }
}

The base keyword here calls the base class constructor that matches the provided parameter overload.

Comments

[catfood]

This is a duplicate question. stackoverflow.com/questions/12051/… Googling "base class constructor parameters" would have brought it right to you.

[phoog]

You say "you can't instantiate an abstract class," but that's not entirely true. If you create an instance of the non-abstract derived class, that instance is also an instance of the abstract base class. It is also an instance of the System.Object class.

[Chris Sinclair]

FYI, even if it's an abstract class, it can have defined custom constructors with parameters that can be passed in. They can't be instantiated/called directly but instead are referenced in derived types by using the base keyword with the derived constructors.

[Ahmn21]

Is the default constructor still invoked if base constructor is called as :base(param) ?

[BradleyDotNET]

No. That constructor would have to call this() @Ahmn21