Calling a method when another method is called

Question

This might be a stupid question, but here goes.

I have the following problem:

public class MyBaseClass
{
    public void SomethingAwesome()
    {
        //Awesome stuff happens here, but only when the Something() method
        //is called in the other classes.
    }
}

public class SomeClass : MyBaseClass
{
    public void Something()
    {
        //Something happens here
    }
}

public class SomeOtherClass : MyBaseClass
{
    public void Something()
    {
        //Something else happens here
    }
}

MyBaseClass has a method which needs to be called when the Something() method is called in the class that inherits from it.

The idea behind this is that I need to log when this method is called for lots of boring corporate reasons. I would rather have a base class which automatically audits when a method is called, rather than having the developer call the method himself/herself.

Can something like this be achieved? If so, how?

I've considered partial methods, but that would require classes with the same name, which isn't possible in this scenario.

Jon Skeet · Accepted Answer · 2015-02-11T09:59:45.533

6

It sounds like you want the template method pattern:

public abstract class MyBaseClass
{
    public void Something()
    {
        // Code from SomethingAwesome here, or keep SomethingAwesome
        // separate and call it from here
        SomethingImpl();
    }

    protected abstract void SomethingImpl();
}

public class SomeClass : MyBaseClass
{
    protected override SomethingImpl()
    {
        // Something happens here
    }
}

That's assuming you're happy for MyBaseClass to have a public Something method, of course - if it doesn't declare Something (in some way) then the two Something methods in the derived classes are unrelated.

edited Feb 11 '15 at 09:59

answered Feb 11 '15 at 09:32

Jon Skeet

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This is somewhat what I am after, however the abstract SomethingImpl() needs to have an implementation. What I'm after is SomethingImpl() gets called in SomeClass, and called in the base class. – Mike Eason Feb 11 '15 at 09:34
@helb: That *will* happen - because the only way of calling the subclass code is via the base class method. – Jon Skeet Feb 11 '15 at 09:34
@MikeEason: It doesn't need to have an implementation if it's abstract. I don't really follow your comment, but this really *is* what you want, I'm sure. If you don't want `MyBaseClass` to be abstract, you could make `SomethingImpl` just an empty virtual method instead. – Jon Skeet Feb 11 '15 at 09:35
2

I think there's a small typo: "SomethingAwful" should perhaps say "SomethingAwesome"? – Matthew Watson Feb 11 '15 at 09:36
Yes, you're absolutely right. Thank you very much sir. – Mike Eason Feb 11 '15 at 09:38

score 1 · Answer 2 · answered Feb 11 '15 at 09:33

1

public class MyBaseClass
{
    public void SomethingAwesome()
    {
         // ...
    }

    public void Something()
    {
         SomethingImpl();
         SomethingAwesome();
    }

    protected abstract void SomethingImpl();
}

answered Feb 11 '15 at 09:33

Sebastian Negraszus

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Calling a method when another method is called

2 Answers2