Question

I have a base class that has a method that gets executed by derived classes.
The method is raised by a constructor of the derived class and by some methods or properties in it.
I need to determine if that came from inside the instance constructor of that derived class or after that (in runtime).

The following example explains what I need:

public class Base
{
    public Base()
    {

    }

    protected void OnSomeAction(object sender)
    {
        // if from derived constructor EXIT, else CONTINUE
    }
}

public class Derived : Base
{
    public void Raise()
    {
        base.OnSomeAction(this); // YES if not called by constructor
    }

    public Derived()
    {
        base.OnSomeAction(this); // NO
        Raise(); // NO
    }
}

class Program
{
    static void Main(string[] args)
    {
        var c = new Derived(); // NO (twice)
        c.Raise(); // YES
    }
}

The problem is that I cannot change the signature or arguments because I cannot alter derived classes. Basically what I was thinking is to determine if the derived class (sender) is fully constructed.

So the implementation is as is. I cannot do changes in the base class that break derived classes. I can do changes only to the base class :/

Is this possible in some way, good or not? Even some reflection magic or similar hacky approach is unfortunately welcome as this is a must :/.

Thanks!

Answer 1

Is this possible in some way…

Yes

good or not?

Not. But you already knew that.

Nevertheless, here is one way to do it.

protected void OnSomeEvent( object sender, EventArgs e )
{
    var trace = new StackTrace();
    var frames = trace.GetFrames();

    for ( int idx = 0; idx < frames.Length; idx++ )
    {
        MethodBase method;

        method = frames[idx].GetMethod();
        if ( method.ReflectedType == typeof(Derived) && method.IsConstructor )
        {
            return;
        }
    }
    /* Perform action */
}

source