CODEWITHSUNDEEP
c#eventsstylecopgeneric-interface
James
James

Reputation: 9975

StyleCop and MultipleGenericInterfaces and CA1033

I have an interface IBakeable<T> which has an event OnCooked

A couple of data classes Pie and Bread

And I have a classes which implements IBakeable<Pie> and IBakeable<Bread>

In order to implement this I think I have to implement the interfaces explicitly

public class BaseHeatSource: IBakeable<Pie>, IBakeable<Bread>
{
    private event EventHandler OnPieCooked;
    event EventHandler IBakeable<Pie>.OnCooked
    {
        add {OnPieCooked+= value;}
        remove {OnPieCooked-= value;}
    }

    private event EventHandler OnBreadCooked;
    event EventHandler IBakeable<Bread>.OnCooked
    {
        add {OnBreadCooked+= value;}
        remove {OnBreadCooked-= value;}
    }
}

And the class is inherited

public class Oven: BaseHeatSource
{

}

public class Fire: BaseHeatSource
{

}

Now I get the equivalent of:

CA1033 Interface methods should be callable by child types

Make 'BaseHeatSource' sealed (a breaking change if this class has previously shipped), implement the method non-explicitly, or implement a new method that exposes the functionality of 'IBakeable.OnCooked.add(EventHandler)' and is visible to derived classes.

Msdn states:

If the derived type re-implements (explicitly) the inherited interface method, the base implementation can no longer be accessed. The call through the current instance reference will invoke the derived implementation; this causes recursion and an eventual stack overflow.

Note that adding

protected void AddOnBreadCookedHandler(EventHandler handler)
{
    this.OnBreadCooked += handler;
}

does not resolve the rule.

Do I have to suppress this rule? or is there a way of fixing it?

Upvotes: 1

Views: 720

Answers (1)

James
James

Reputation: 9975

Solved this via Composition...

Created an abstract Bakeable<T> class as

public abstract Bakeable<T> : IBakeable<T>
{
    event EventHandler OnCooked;

    public Cooked(object sender)
    {
        var handler = this.OnCooked;
        if (handler != null)
        {
            handler(sender, new EventArgs());
        }
    }
}

Created an IBakeable<Pie> property which is the Bakeable<Pie> class

for firing the event called BakeablePie.Cooked;

for attaching to the event it simply became oven.BakeablePie.OnCooked += customerWantsPie.Eat

I'm really not sure how this helps me in regard to Hans' comment in order to cook more things I need to add more properties

Upvotes: 0

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