I am creating an abstract class. I want each of my derived classes to be forced to implement a specific signature of constructor. As such, I did what I would have done has I wanted to force them to implement a method, I made an abstract one.

public abstract class A
{
    abstract A(int a, int b);
}

However I get a message saying the abstract modifier is invalid on this item. My goal was to force some code like this.

public class B : A
{
    public B(int a, int b) : base(a, b)
    {
        //Some other awesome code.
    }
}

This is all C# .NET code. Can anyone help me out?

Update 1

I wanted to add some things. What I ended up with was this.

private A() { }

protected A(int a, int b)
{
    //Code
}

That does what some folks are saying, default is private, and the class needs to implement a constructor. However that doesn't FORCE a constructor with the signature A(int a, int b).

public abstract class A
{
    protected abstract A(int a, int b)
    {


    }
}

Update 2

I should be clear, to work around this I made my default constructor private, and my other constructor protected. I am not really looking for a way to make my code work. I took care of that. I am looking to understand why C# does not let you do this.